Journal of Sexual Medicine and Reproductive Health

Research Article © Ellis L and Hoskin AW, 2019

Evidence for Androgenic Influences on Self-Rated Health Lee Ellis1* and Anthony W. Hoskin2 1Department of Anthropology and Sociology, University of Malaya, Malaysia 2Department of Sociology, Idaho State University, USA

Abstract Background: According to most studies, males self-report being physically and mentally healthier than females. The present study sought to determine if might influence health.

Methods: Self-reports of physical and mental health were obtained from college students in Malaysia (N = 2,058) and the United States (N = 2,511). exposure was assessed based on five self-reported measures that were then factor analyzed. A clear two- factor solution resulted from the analysis: muscularity, physical strength, and athletic ability loaded onto a muscular coordination factor, while adult height and 2D:4D finger length measure loaded onto a .

Results: As hypothesized, for males and females in both countries, self-rated physical and mental health were both positively correlated to a significant degree with the muscular coordination androgen factor. The only significant correlation between self-rated health and the bone growth androgen factor was negative among the Malaysian sample.

Conclusions: Androgenic influences on muscular coordination appear to coincidentally alter self-rated physical and mental health. This conclusion conflicts with proposals that men and women would provide the same self-ratings of health if it were not for sex role training and discrimination.

Keywords: Self-rated physical health; Self-rated mental health; Androgen-influenced traits; Sex differences; Sex roles

Introduction Three plausible explanations have been offered for sex differences in self-perceived health: First, some have asserted that Most studies have found self-reported physical health to be the main cause is sex discrimination along with sex role training. higher among males than among females [1-8], although some For example, Molarius [7], argued that women’s self-rated health based on college student samples [9,10]. Research suggests that have failed to find significant differences, particularly studies security as men and were not treated in a condescending manner the sex difference is found not only for perceptions of overall towould a larger be the extent same than as that men”. for Similar men “if proposals they had havesimilar been financial made health, but for reports of symptoms and for rates of morbidity in recent years by Borrell [20,21]. In the case of sex differences [11]. Whereas men tend to have higher rates of chronic disease in self-reported mental health, proposals that sex discrimination and mortality, women tend to experience illnesses of a less may also be an important determinant, especially regarding serious and more transient nature [12]. depression, have also been made [20,22-24]. In most studies of self-rated mental health, ratings by Second, sex differences in self-assessed health have been males are also higher than those provided by females [13-16]. attributed to differences in levels of activity and exercise [25]. evidence that in nearly all countries men die 4 to 5 years earlier Paradoxically, high self-rated health by males flies in the face of with elevated mood, reduced stress, and improved physical than women [17-19]. (It is true that some of the life expectancy healthSpecifically, [26-31]. studies This indicate coincides that with regular numerous exercise studies is associated showing difference between males and females is due to greater risk- that males are more physically active and more likely to regularly exercise than females [32]. self-rated levels of health). taking among young males – a fact that would not be reflected in A third proposal is that exposure to androgens (male sex ) could contribute to average sex differences in

Submitted: 12 December 2019 | Accepted: 09 January 2020 | Published: self-reported health [33]. Support for this view is currently 13 January 2020 fragmentary. It includes studies linking various physical disorders

*Corresponding author: Lee Ellis, Department of Anthropology and of prenatal exposure (as will be discussed in more Sociology, University of Malaya, Kuala Lumpur, 50603, Malaysia, Email: with measures of 2D:4D finger length ratio, a reputed measure [email protected] been found associated with high ratings of various types of joint Copyright: © 2020 Ellis L and Hoskin AW. This is an open-access pain,detail including below). For osteoarthritis example, high [34], 2D:4D and temporomandibular finger length ratios havejoint article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in (TMJ) disorders [35]. Four direct lines of evidence linking self- any medium, provided the original author and source are credited. rated health and androgens were located. One came from a study

Ellis L, Hoskin AW (2020) Evidence for Androgenic Influences on Citation: between circulating testosterone and self-rated physical health Self-Rated Health. J Sexual Med Reprod Health 3: 9. asof wellwomen as a in reduction which a insignificant depression positive symptoms correlation [36]. Another was found was

J Sexual Med Reprod Health 2: 9 1/9 1147. 1(1): Res Clin Cardiol J a study of men in which circulating testosterone was positively correlated with self-rated health [37]. The remaining two refined in English. It was then translated into Bahasa Malaysia, correlations between age-controlled circulating testosterone and Malaysia’s official language since its independence from Great self-ratedstudies were health of elderly[38,39]. men, Men mightboth reporting report high significant levels of physicalpositive Britain in 1957. To ensure that the Malaysian translation was and mental health due to testosterone’s reduction in sensitivity equivalent to the English version, the Malaysian questionnaire to aches and pain, and to its tendency to elevate mood [33,40]. coveredwas back-translated a wide variety intoof topics, English only untila few discrepanciesof which are part were of theeliminated. present study. Both questionnaires were four pages in length and Given that androgen studies of self-rated health have been limited to circulating levels of testosterone, the present study was Androgen-Influenced variables undertaken to explore the relationship between organizational androgens and self-assessed health. This was done by obtaining androgen exposure in the late 20th Century [43], a subtle but fairlySince easily it wasobserved first identified trait known as a as likely the 2D:4Dbiomarker ratio of(or prenatal simply exposure (2D:4D, adult height, muscularity, physical strength, 2D:4D) has come to be widely utilized in research on traits that andself-reported athletic ability) measures along of fivewith biomarkers self-ratings for of physical high androgen health and mental health. We hypothesized that self-ratings of physical and mental health would be positively correlated with androgen 2D:4D,are suspected with males as being having influenced lower ratios, by prenatal meaning androgens. that the relative Among exposure, even within each sex. lengththe findings of their are 4 thatth there are well-establishednd sex differences in Method longer than for most females [44-49]. These sex differences are present even among finger newborns, compared albeit to totheir a slightly 2 finger lesser is slightlydegree The study’s sample was comprised of undergraduate college than among adults [50,51]. students in Malaysia (N = 2,059) and the United States (N = 2,247). These two populations were chosen in order to see if Studies have also shown 2D:4D to be statistically associated results would be robust across two very different cultures. The with several other sexually dimorphic physical traits such as proportional representation of respondents in terms of gender, birth weight [52,53], adult height [54,55], physical strength and marital status, and ethnicities are shown in Table 1 along with muscularity [56-58], and athletic ability [59-62]. Consequently, it their average ages. Greater numbers of females than males in is reasonable to consider them physical biomarkers for androgen both countries were largely due to more females attending college in both Malaysia and the United States in recent years to provide estimates of 2D:4D as well as estimates of their height, [41,42] (Table1). physicalexposure. strength, In the research muscularity, questionnaire, and athletic respondents ability. were asked The questionnaire The r2D:4D Measure The questionnaire used in this study was developed and

Most studies that have compared the relative finger lengths on Table 1: Demographic composition of the samples. Demographic Traits Malaysian Sample United States Sample Gender Males 652 (31.7%) 1,027 (40.9%) Females 1,406 (68.3%) 1,484 (59.1%) 2,058 2,511

MeanTOTAL (standard deviation) 20.86 (2.36) 23.96 (9.27) Age Range 18-42 17-81 2,058 2,511 Marital Status SingleTOTAL (including engaged, domestic partners) 1,971 (95.7%) 2,004 (79.8%) Married 37 (1.8%) 341 (13.6%) Divorced/separated/widowed/single mom 1 (0.0%) 80 (3.2%) No response or other 50 (2.4%) 86 (3.4%) 2,058 2,511

TOTAL 0 1,394 (55.5%) Ethnicity 0 173 (6.9%) White/European Ancestry 0 745 (29.7%) Black/African Ancestry 1,474 (71.6%) 5 (0.2%) Hispanic/Latin/Native American 477 (23.2%) 66 (2.6%) Malay/Bumiputera/Indonesian 85 (4.1%) 51 (2.0%) East Asian (Chinese, “Asian” in US) 3 (0.1%) 64 (2.5%) NoOther (or Asian unintelligible) (primarily response Indian) 19 (0.9%) 13 (0.5%) Other (Mixed, Arabic, Persian, Euro-Asian) 2,058 2,511

TOTAL J Sexual Med Reprod Health 2: 9 2/9 both hands have concluded that the right hand provides a more Four additional androgen-Influenced traits reliable measure of prenatal androgen exposure than does the the left hand [49,63-67].Therefore, we limited our measurement prenatal androgen exposure although its reliability has been to the right hand, and will use the term r2D:4D to reference it. disappointinglyAs noted above, low. 2D:4D Therefore, appears four to additional be a valid biomarkers indicator of androgen exposure were utilized, all of which have been found digits are altered by perinatal androgen exposure remains to to be inversely correlated with 2D:4D: height [54,55], physical be fullyExactly explained, how the but relative it is well lengths established of the second that testosterone and fourth strength and muscularity [56-58], and athletic ability [59,61,62]. androgens normally rise seems to coincide with a growth spurt promotes bone growth [68-71]. Also, a period when prenatal in the fourth digit [55,63,72]. metrics,Adult while height the was U.S. measured sample responded by simply in asking feet and all inchesrespondents which to report their height. In Malaysia, reports were provided in Using a variety of research designs, several studies have were converted to metrics. The remaining three traits were physical strength, muscularity, and athletic ability. To obtain these measurements, confirmed that 2D:4D is a relatively valid biomarker for perinatal precise instruments, it is a reliable measure [75], but researchers respondents were asked to use an eleven-point scale with androgen exposure [48,63,73,74]. At least when measured with yourself on the following traits (0 10 have characterized it as “valid, though weak” [76], and “a very the following instructions: Being as objective as possible, rate ‘noisy’ indicator” [77]. meaning “not at all” to nd th measuring the relative lengths of the 2 and 4 digits involves meaningPhysical “the strength most extreme _____ degree possible”): obtainingAlthough X-ray it isimages infrequently [67,78]. used,Much the more “gold common standard” methods for Being muscular _____ involve physically measuring the distance between the tip of the Athletic ability _____ From the standpoint of accuracy, it obviously would have finger to the basal crease where the finger connects to the palm or scanned images of the hand and then using calipers to estimate been preferable to have had each of these traits measured with [79]. Additional measures have been obtained from photocopies objective instruments overseen by trained researchers. However, on various self-estimates made by respondents themselves to provide anonymity, and to save time and expense given large their relative lengths [55,80,81]. A few studies have relied [66,82,83]. sample sizes in both countries, we relied entirely on self-reports. Correlating and factor analyzing the Androgen- self-estimate. They did so after reading the following: Hold up In the present study, respondents were asked to provide a Influenced traits

2thend back of your right hand so thatth you can see all five fingers. adult height, physical strength, muscularity, and athletic ability. With your thumb as the first finger, compare the lengths of your As already documented, 2D:4D is inversely associated with (pointing) finger with your 4 (ring) finger. Which is longer? by exposing the body to testosterone and/or other androgens (check____ one Index of (pointing)the five responses finger considerably below) longer Such findings are predictable since all of these traits are influenced ____ Index (pointing) finger slightly longer U.S.,[53,84]. the inverted Table 2 r2D:4D provides variable confirmation positively of correlates these findings with adult with ____ They are almost exactly the same length height,respect physicalto the present strength, study. muscularity, Specifically, andin both athletic Malaysia ability, and andthe these variables in turn all positively correlate with one another. ____ Ring (4th) finger slightly longer ____ Ring (4th) finger considerably longer i.e., in the Malaysian sample, the associations between physical strengthAll but two and ofthe these inverted correlations r2D:4D and were height statistically variables significant, both fell For a subsample of 215 of the U.S. respondents, we obtained both the self-estimate just described and a measure using calipers of scanned images of the right hand. This yielded a slightly short of statistical significance. modest positive correlation of r = .30 between the two measures. traits were interrelated, we subjected them to factor analysis. To determine how closely linked the five androgen-influenced

Because we inverted all of the r2D:4D scores, all five androgen- self-reportWhile highly measure significant was statistically, only modestly and reliable. both measures no doubt each trait meant high androgen exposure. contain measurement error, this coefficient suggests that our influenced traits were in the same direction: i.e., high scores for The results of the factor analysis appear in Table 3 for each we inverted the r2D:4D self-ratings (relative to how they are sex. Without having any limits imposed regarding the number of In order to minimize confusion in interpreting the results,higher factors to be extracted, the same factors emerged for both males androgen exposure. This pattern means that high r2D:4D scores and females. Our inverted r2D:4D measure loaded very heavily normally presented). Thus, the higher r2D:4D ratios reflect along with adult height onto Factor 2. Since both of these traits traits discussed below; all are in the positive direction. conform to high scores for the other four androgen-influenced pertain to skeletal structures (i.e., growth of the fingers and J Sexual Med Reprod Health 2: 9 3/9 Table 2: U.S. sample in the lower left portion. Spearman rank correlations between the five androgen-influenced traits for the Malaysian sample in the upper right portion and for the Height r2D:4D (inverted) Physical strength Muscularity Athletic ability (centimeters) r2D:4D (inverted) --- .102*** .028 .062** .061** Height (centimeters) .093*** --- .026 .300*** .229*** .038 .142*** --- .342*** .355***

PhysicalMuscularity strength .071** .237*** .625*** --- .519*** .085*** .170*** .517*** .605*** ---

Athletic* p < .05; ability ** p < .01; *** p < .001

Table 3:

Factor loadings for the five self-assessed androgen-influenced traits using principal component analysis with varimax rotation. Analyses Males & Females Combined were run on males and femalesMales separately and in combination. (AllFemales loadings above .50 are bolded. Eigenvalues: Factor 1 = 2.096; Factor 1 = 1.075). Self-Rated Androgen-Influenced Factor 1 Factor 1 Factor 2 Factor 2 (Bone (Muscular- Factor 2 (Bone Traits (Muscular- (Muscular- (Bone Growth) Growth) Coordination) Growth) Coordination) Coordination) r2D:4D inverted -.002 .681 .020 .578 -.054 .754 .037 .732 .133 .786 .217 .697

Adult height .827 -.162 .718 -.306 .781 -.193 PhysicalMuscularity strength .859 .061 .829 .179 .833 .215 .787 .225 .796 .196 .784 .250

Athletic ability growth of the body as a whole), we named this second factor the r2D:4D measure is henceforth referred to as inverted r2D:4D. The bone growth factor. the two self-ratings of health. androgen-influenced traits (and factors) were correlated with Results unambiguouslyThe remaining onto three Factor androgen-influenced 1. The communality traits of these – physical three traitsstrength, suggested muscularity, that they and would athletic be appropriately ability – all named loaded the to Table 4. This provides a comparison of averages for all of the Before addressing the study’s hypotheses, attention is drawn important roles in affecting both skeletal growth and muscularity, muscular coordination factor. Even though androgens play (andvariables for the (and two factors) factors according derived fromto gender these and variables) country. were As one all and muscular coordination result from substantially different would expect, scores for the five of the independent variables androgenicour findings regimens are consistent and/or biochemical with evidence pathways that bone [85,86]. growth Dependent variables significantly higher for males than for females. However, only otherphysical studies health limited for the to college U.S. sample student was populations significantly [9,10]. higher in To assess health, research participants were asked to answer males. As noted in the introduction, this is similar to a couple of Androgen biomarkers and self-rated physical health yourself on the following traits (0 10 the following two questions: Being as objective as possible, rate The evidence bearing on the hypothesis that self-rated meaning “not at all” to physical health would be postively correlated with androgen meaningPhysical “the health most ______extreme degree possible”): Mental health ______toexposure Factor is1 (the presented muscular in Table coordination 5a. According factor), to comprised this table, of Data analyses physicalstatistically strength, significant muscularity, positive correlations and athletic exist ability. with However, respect

the 2D:4D measure), was not correlated with self-rated physical traits were associated with one another and with the health health.Factor 2The (the pattern bone growth holds for factor both – countries comprised sampled of adult and height for both and measures,In order we toused determine correlation. how Spearman well the correlation androgen-influenced was used males and females. since the relevant variables were measured at the ordinal level. Androgen biomarkers and self-rated mental health Two-tailed tests of significance were utilized throughout. Table 5b presents evidence bearing on the possible the scores for the r2D:4D measure were inverted. Therefore, our relationship between self-rated mental health and androgen As noted earlier, to make interpretation of findings easier,

J Sexual Med Reprod Health 2: 9 4/9 Table 4: Males Females Trait (or Sex Factor) differences in the androgen-influencedCountry traits and the physical and mental health measures by country and tgender. p Mean SD Mean SD

Malaysia 3.42 1.08 3.14 1.11 5.27 .000 Independent Variables (and Their Two DerivedU.S. Factors) 3.78 0.93 3.35 0.98 10.68 .000 Inverted r2D:4D Malaysia 169.77 6.99 158.23 6.11 35.065 .000 U.S. 178.46 9.31 164.05 7.62 38.412 .000 Adult height (centimeters) Malaysia 6.73 2.27 6.45 2.26 2.638 .008 U.S. 6.70 2.17 5.62 2.34 11.200 .000 Malaysia 4.75 2.53 2.64 2.55 17.485 .000 MuscularityPhysical strength U.S. 5.65 2.45 3.73 2.58 18.734 .000 Malaysia 5.03 2.75 3.59 2.70 11.070 .000 U.S. 6.73 2.55 5.05 2.96 14.251 .000 AthleticFactor ability 1: Muscular Coordin-ation Malaysia 0.21 0.96 -0.33 0.88 11.756 .000 U.S. 0.51 0.96 -.08 1.01 12.740 .000 Malaysia 0.05 0.79 -0.68 0.78 18.469 .000 Androgen Factor U.S. 0.87 0.87 0.14 0.91 18.315 .000 Factor 2: Bone Growth Androgen Factor Malaysia 7.59 2.04 7.58 1.94 0.078 .937 Dependent Variables U.S. 7.70 1.89 7.40 2.17 3.654 .000 Malaysia 7.83 1.97 7.91 1.96 -0.811 .417 MentalPhysical health health U.S. 8.04 2.00 7.99 3.35 .427 .642

Table 5a: gender. Spearman ranks between self-rated physical health and the five androgen-influenced traits (and the two derived factors) by country and Androgen-Influenced Traits Androgen-Influenced Factors Sex Country Physical Athletic Inverted Adult Factor 1 (Muscular Factor 2 (Bone Muscu-larity Strength Ability r2D:4D Height Coordination) Growth) Malaysia .553*** .155*** .201*** .001 -.009 .402*** -.130** U.S. .386*** .311*** .385*** -.015 .053* .413*** -.036 Both Sexes Malaysia .621*** .281*** .335*** -.074 -.023 .501*** -.211*** Males U.S. .460*** .408*** .469*** -.019 -.032 .509*** -.106** Malaysia .520*** .103** .145*** .036 -.024 .367*** -.119** Females U.S. .331*** .242*** .328*** -.031 .063* .354*** -.044 * p < .05; ** p < .01; *** p < .001, two-tailed

Table 5b: country and gender. Spearman rank correlations between self-rated mental health and the five androgen-influenced traits (and two derived factors) by Androgen-Influenced Traits Androgen-Influenced Factors Factor 2 Sex Country Physical Athletic Inverted Adult Factor 1 (Muscular Muscu-larity (Bone Strength Ability r2D:4D Height Coordination) Growth) Malaysia .514*** .075** .134** .015 -.062** .307*** -.145** U.S. .286*** .169** .215** .007 .046* .250** -.013 Both Sexes Malaysia .594*** .227*** .258*** -.067 -.066 .424*** -.226*** Males U.S. .333*** .215*** .266*** -.021 .010 .315*** -.067 Malaysia .480*** .022 .093** .059* -.073* .280*** -.115*** Females U.S. .259*** .145*** .180*** .016 .060* .224*** -.003 * p < .05; ** p < .01; *** p < .001, two-tailed

this pattern holds for both countries and for both sexes and it holds true for all three androgen measures comprising Factor 1. exposure. Its results are similar to those for self-rated physical health. Factor 1 – incorporating physical strength, muscularity, and athletic ability – is significantly and positively correlatedwith In the case of the remaining two androgen exposure measures with mental health self-ratings. As with physical health ratings, – i.e., those comprising Factor 2 (the bone growth factor) – there J Sexual Med Reprod Health 2: 9 5/9 is actually a negative correlation for the Malaysian sample, but this conversion, operates in conjunction with the and the lack of relevant research leaves us unable to explain the humanconverted growth to estradiol , (via to the elongate enzyme and aromatase). strengthen After the making unexpectednot for the U.S. sample. This finding is contrary to our hypothesis, development and functioning more directly, although Discussion may[88-91]. still Ashave a steroid, some role testosterone to play in theappears process to promote[91-95]. muscular males report being healthier than females, both physically and on single-item, self-rated responses. This is all but unavoidable As noted in the introduction, most studies have found that mentally, with a few exceptions involving samples drawn from for measuringAmong the limitationsself-reported of this health study in are a non-clinical that measures setting, are based but

precisely with physiologically-based instruments. Nonetheless, college students. In the present study of college students, U.S. the androgen-influenced traits could have been measured more Malaysianmales rated students their physical regarding health physical significantly health. higher Self-ratings than did of to some new directions that may be taken to understand how females, but no significant difference was found amongst the as an exploratory study, our findings are suggestive with respect in either country (Table 4). Obviously, there is a need to discover We also see our indirect measurement of androgens as actually whymental sex health differences were not are significant found in self-rateddifferent for health males among and females broad beingandrogens advantageous may influence over direct traits measurements such as self-assessed of testosterone health. populations but sometimes not among college students. and other androgens, since direct measures only tap into the levels of these hormones over a short period of time. Our indirect The main purpose of this study was to determine if variations measurements gage much more long term prenatal exposure to in physical and mental health self-ratings could be partly due to androgens. exposure to organizational androgens. Five androgen exposure measures were utilized: 2D:4D, adult height, physical strength, muscularity, and athletic ability. These measures were factor Another limitation was that only college students were analyzed and shown to load unambiguously onto two factors: was found only among the U.S. male sample, our study probably sampled. Because a significant sex difference in self-rated health Factor 1, termed the muscular coordination factor, and Factor provides a minimal estimate of the extent to which androgens 2, named the bone growth factor. For this study, values for play a role in self-rated health. Moreover, the 2D:4D digit ratio the 2D:4D measure were inverted, so that high scores would thus providing a low-reliability marker for prenatal androgen exposure.is recognized Nonetheless, as a “noisy” evidence biomarker presented of androgenhere that androgens exposure, measurescorrespond and with on both high androgen androgen exposure exposure. factors In all (Table cases, 4). males are related to physical and mental health suggests that further scored significantly higher than females on all five androgen research along these lines is in order. Results from this study strongly support the conclusion that androgens do have effects on self-ratings of both physical health Acknowledgements and mental health. This conclusion directly contradicts those who The following individuals assisted in recruiting research argue that sex differences in self-ratings of health can actually be entirely explained in terms of sex role training and societal Widmayer.participants Funding for this forstudy: the collectionDrew H. Bailey, of data David utilized Geary, in this Richard study view that organizational androgens improve health indirectly via wasD. Hartley, provided Richard in part Lippa, by Emi a research Prihatin, grant Anthony from Walsh, the University and Alan increaseddiscrimination physical [7,21]. exercise. Our findings are also consistent with the The strongest apparent effects of androgens on self-rated visitingof Malaya professor. to its Department of Anthropology and Sociology (Number RG143-10HNE) while the first author was there as a with three prior studies indicating that circulating testosterone References levelshealth arewere positively positive, correlated as we hypothesized. with self-rated This health finding [36,38,39]. coincides 1. However, the positive effects we observed were based on indirect, The role of gender in the association of social capital, social support, andChemaitelly economic H, securityKanaan C,with Beydoun self-rated H, Chaaya health M, among Kanaan older M, Sibaiadults AM. in indicate that only the effects of androgen regimens pertaining rather than direct, measures of androgens, and our findings 2. deprived communities in Beirut. Qual Life Res. 2013; 22, 1371-1379. least in our Malaysian sample, there was also a weak but still T, et al. Social determinants of self-reported health in women and to muscular coordination affected self-ratings of health. At Hosseinpoor AR, Williams JS, Amin A, De Carvalho IA, Beard J, Boerma bone growth factor that also appears to have affected self-rated 2012; 7: e34799. significant negative effect of androgen regimens associated with men: understanding the role of gender in population health. PLoS One, health. This was entirely unexpected and obviously needs to be 3. replicated. Kroenke K, Spitzer RL. Gender differences in the reporting of physical Without attempting to offer a detailed explanation for 4. and somatoform symptoms. Psychosomatic Med. 1998; 60: 150-155. biochemical pathways whereby androgens promote muscular Li H, Zhu Y. Income, income inequality, and health: Evidence from 5. China. Journal of Comparative Economics. 2006; 34: 668-693. developmentthese findings, and it skeletal is almost growth certainly are relevantnot the same to note [86,87]. that For the example, to promote bone growth, testosterone needs to be nationalKawada T,survey, Wakayama 1989-2004. Y, Katsumata Gender M, Med. Inagaki 2009; H, 6: Otsuka 329-334. T, Hirata Y, et al. Patterns in self-rated health according to age and sex in a Japanese

J Sexual Med Reprod Health 2: 9 6/9 6. How chronic conditions contribute to gender inequalities in self-rated 77-91. Malmusi D, Artazcoz L, Benach J, Borrell C. Perception or real illness? and sex differences in mental health. J Health Social Behav. 1989; 30: 25. 7. health. Eur J Public Health. 2012; 22: 781-786. 1994;Ross CE, 35: Bird 161-178. CE. Sex stratification and health lifestyle: consequences theMolarius higher A, prevalenceGranstrom F, of Feldman poor self-rated I, Blomqvist health MK, in Pettersson women than H, Elo in for men’s and women’s perceived health. J Health and Social Behav. S, et al. Can financial insecurity and condescending treatment explain 26. physical health in adulthood: Testing physically active leisure as a Health. 2012; 11: 50-57. Arai SM, Mock SE, Gallant KA. Childhood traumas, mental health and men? A population-based cross-sectional study in Sweden. Int J Equity 8. 27. buffer. Leisure. 2011; 35: 407-422. Todorova IL, Tucker KL, Jimenez MP, Lincoln AK, Arevalo S, Falcón Fox KR, Stathi A, McKenna J, Davis MG. Physical activity and mental LM. Determinants of self-rated health and the role of acculturation: 585. well-being in older people participating in the Better Ageing Project. implications for health inequalities. Ethnicity & Health. 2013; 18: 563- 28. 9. Eur J applphysiol. 2007; 100: 591-602. Jewett R, Sabiston CM, Brunet J, O’Loughlin EK, Scarapicchia T, Castrén J, Huttunen T, Kunttu K. Users and non-users of web-based conditions and self-reported health status (a cross-sectional study). O’Loughlin J. School sport participation during adolescence and health advice service among Finnish university students–chronic 644. mental health in early adulthood. J Adolescent Health. 2014; 55, 640- 29. 10. BMC Med Inform Decision Making. 2008; 8: 8. Niemann C, Wegner M, Voelcker-Rehage C, Holzweg M, Arafat AM, Noor NM, Rahman SA, Farooqui J, Nasr AM, Noon HM. Psychological performance and saliva testosterone in preadolescent school children. 46: 235-245. Budde H. Influence of acute and chronic physical activity on cognitive profiles of effeminate, male, and female students. Psychologia. 2003; 11. 30. Mental Health and Physical Activity. 2013. 6: 197-204. Gove WR, Hughes M. Possible causes of the apparent sex differences 126-146. Salmon P. Effects of physical exercise on anxiety, depression, and in physical health: An empirical investigation. Am Sociol Rev. 1979; 61. 12. sensitivity to stress: a unifying theory. Clin Psychol Rev. 2001; 21: 33- 31. Strö Gijsbers van Wijk CMT, Kolk AMM, van den Bosch WJHM, van den hle A. Physical activity, exercise, depression and anxiety disorders. Hoogen HJM. Male and female morbidity in general practice: The 678. 32. J Neural Transm. 2009; 116: 777-784. nature of sex differences. Social Science & Medicine. 1992; 35: 665- 13. Ellis L, Hershberger S, Field E, Wersinger S, Pellis S, Geary D, et al. Sex differences: Summarizing more than a century of scientific research. Hutton K, Nyholm M, Nygren JM, Svedberg P. Self-rated mental health 33. New York: Psychology Press. 2008. and socio-economic background: A study of adolescents in Sweden. 14. BMC Public Health. 2014; 14: 394-402. Fillingim RB. Sex, gender, and pain: Women and men really are 34. different. Curr Rev Pain. 2000; 4: 24-30. Kim BJ, Harris LM. Social capital and self-rated health among older 15. Korean immigrants. J Applied Gerontol. 2013; 32: 997-1014. prenatalde Kruijf androgen M, Kerkhof exposure HJ, Peters and the MJ, risk Bierma-Zeinstra for osteoarthritis S, Hofman and pain. A, Uitterlinden AG, et al. Finger length pattern as a biomarker for O’Regan C, Cronin H, Kenny RA. Mental health and cognitive function. Osteoarthr Cartil. 2013; 21: S266. In A. Barrett G. Savva V. Timonen & R. A. Kenny (Eds), Fifty Plus in 35. 16. Ireland, 155-166. Dublin: Irish Longitudinal Study on Ageing. 2011. Sanders AE, Slade GD, Bair E, Fillingim RB, Knott C, Dubner R. General Hicks T, Miller E. College life styles, life stressors and health status: health status and incidence of first-onset temporomandibular 17. Differences along gender lines. J College Admission. 2006; 192: 22-29. T51-T62. disorder: The OPPERA prospective cohort study. J Pain. 2013; 14: Idler EL, Benyamini Y. Self-rated health and mortality: A review of 36. 18. twenty seven community studies. J Health Soc Behav. 1997; 38: 21-37. Korenman S. Correlates of circulating androgens in mid-life women: health an independent index for mortality among older people in Santoro N, Torrens J, Crawford S, Allsworth JE, Finkelstein JS, Gold EB, Ng N, Hakimi M, Santosa A, Byass P, Wilopo SA, Wall S. Is self-rated Metab. 2005; 90: 4836-4845. the study of women’s health across the nation. J Clin Endocrinol 19. Indonesia? PloS one. 2012; 7: e35308. 37.

Oksuzyan A, Juel K, Vaupel JW, Christensen K. Men: Good health and LeBlanc ES, Wang PY, Lee CG, Barrett-Connor E, Cauley JA, Hoffman high mortality. Sex differences in health and aging. Aging Clinical and 3863.AR. Higher testosterone levels are associated with less loss of lean 20. Experimental Research. 2008; 20: 91-102. body mass in older men. J Clin Endocrinol Metab. 2011; 96: 3855- 38. ä Borrell C, Muntaner C, Gil-González D, Artazcoz L, Rodríguez-Sanz M, of sex hormone concentrations with health and life satisfaction in Medicine.Rohlfs I, et 2010; al. Perceived 50: 86-92. discrimination and health by gender, social Eskelinen SI, Vahlberg TJ, Isoaho RE, Kivel SL, Irjala KM. Associations class, and country of birth in a Southern European country. Preventive 21. 39. elderly men. Endocr Pract. 2007; 13: 743-749.

Lee SY, Kim SJ, Yoo KB, Lee SG, Park EC. Gender gap in self-rated health reproductiveHsu B, Cumming hormone RG, Blyth levels FM, to Naganathan self-rated health V, Le Couteurand health-related DG, Seibel in South Korea compared with the United States. Int J Clin Health MJ, et al. Longitudinal and cross-sectional relationships of circulating 22. Psychol. 2016; 16: 11-20. Metab. 2014; 99: 1638-1647. Sex Roles. 1982; 8: 607-623. quality of life in community-dwelling older men. J Clin Endocrinol Horwitz AV. Sex-role expectations, power, and psychological distress. 40. 23. Barrett-Connor E, Von Mühlen DG, Kritz-Silverstein D. Bioavailable 24. Radloff L. Sex differences in depression. Sex roles. 1975; 1: 249-265. testosterone and depressed mood in older men: the Rancho Bernardo Rosenfield S. The effects of women’s employment: Personal control Study. J Clin Endocrinol Metab. 1999; 84: 573-577.

J Sexual Med Reprod Health 2: 9 7/9 41. grip strength (but not hand grip endurance) in men (but not in education and the emerging gender gap in college completion. Demography.Diprete TA, Buchmann2006; 43: 1-24. C. Gender-specific trends in the value of 59. women). Evolution and Human Behavior. 2012; 33: 780-789. 42. Shawn F. Dorius, Glenn Firebaugh. Trends in global gender inequality. Soc Forces. 2010; 88: 1941-1968. Bennett M, Manning JT, Cook CJ, Kilduff LP. Digit ratio (2D:4D) and 60. performance in elite rugby players. J Sports Sci. 2010; 28: 1415-1421. 43. nd to 4th 30:Giffin 135-138. NA, Kennedy RM, Jones ME, Barber CA. Varsity athletes have ofManning testosterone, JT, Scutt luteinizing D, Wilson J, hormone Lewis-Jones and DI. oestrogen. (1998). The Hum ratio Reprod. of 2 lower 2D:4D ratios than other university students. J Sports Sci. 2012; 61. Hö 1998; digit13: 3000-3004. length: A predictor of sperm numbers and concentrations prowess: Substantial relationships but neither hand out-predicts the 44. nekopp J, Schuster M. A meta-analysis on 2D:4D and athletic 62. D, Suchecka‐Racho growthGillam L, patterns, McDonald sexual R, Ebling dimorphism FJ, Mayhew and lateral TM. Human asymmetry 2D (index) from 4and to other. Personality and Individual Differences. 2010; 48: 4-10. 4D (ring) finger lengths and ratios: Cross ‐sectional data on linear 2005;Pokrywka 17: 796-800. L, Rachoń ń K, Bitel L. The second to 45. Hö fourth digit ratio in elite and non‐elite female athletes. Am J Hum Biol. 60 years of age. J Anat. 2008; 213: 325-335. 63. nekopp J, Watson S. Meta-analysis of digit ratio 2D:4D shows 630. Brown WM, Finn CJ, Breedlove SM. Sexual dimorphism in digit-length greater sex difference in the right hand. Am J Hum Biol. 2010; 22: 619- 64. 46. ratios of laboratory mice. Anatomical Record. 2002; 267: 231-234. Grimbos T, Dawood K, Burriss RP, Zucker KJ, Puts DA. Sexual Lippa R A. Finger lengths, 2D:4D ratios, and their relation to gender- 121. orientation and the second to fourth finger length ratio: A meta- related personality traits and the Big Five. Biol Psychol. 2006; 71: 116- 65. 47. analysis in men and women. Behav Neurosci. 2010; 124: 278-287. nd th differences in tax compliance: Differentiating between demographic differences in 2 to 4 Kastlunger B, Dressler SG, Kirchler E, Mittone L, Voracek M. Sex 80:Manning 161-168. JT, Stewart A, Bundred PE, Trivers RL. Sex and ethnic digit ratios of children. Early Hum Dev. 2004; 48. N. The ratio of second-and fourth-digit sex, gender-role orientation, and prenatal masculinization (2D:4D). J 66. lengths and congenital adrenal hyperplasia due to 21-hydroxylase Economic Psychology. 2010; 31: 542-552. Okten A, Kalyoncu M, Yariş Manning JT, Morris L, Caswell N. Endurance running and digit ratio (2D:4D): Implications for fetal testosterone effects on running speed 49. deficiency. Early Hum Dev. 2002; 70: 47-54. 67. and vascular health. Am J Hum Biol. 2007; 19: 416-421. Williams TJ, Pepitone ME, Christensen SE, Cooke BM, Huberman Nature. 2000; 404: 455-456. Xi H, Li M, Fan Y, Zhao L. A comparison of measurement methods AD, Breedlove NJ, et al. Finger-length ratios and sexual orientation. 50. and sexual dimorphism for digit ratio (2D:4D) in Han ethnicity. Arch 68. Sexual Behavior. 2014; 43: 329-333. Knickmeyer RC, Woolson S, Hamer RM, Konneker T, Gilmore JH. 2D:4D Diabetes Obes. 2010; 17: 284-292. Ebeling PR. Androgens and osteoporosis. Curr Opin Endocrinol ratios in the first 2 years of life: Stability and relation to testosterone 69. 51. exposure and sensitivity. Horm Behav. 2011; 60: 256-263. development of sex differences in digital formula from infancy in the McIntyre MH, Ellison PT, Lieberman DE, Demerath E,Towne B. The Ventura T, Gomes MC, Pita A, Neto MT, Taylor A. Digit ratio (2D: 4D) in newborns: Influences of prenatal testosterone and maternal 272:1473-1479. 52. Fels Longitudinal Study. Procedings of the Biological Sciences. 2005; environment. Early Hum Dev. 2013; 89: 107-112. 70. Danborno B, Adebisi S, Adelaiye A, Ojo S. Relationship between digit testosterone surge is required for normal adult bone size but not for 127-130. Sims NA, Brennan K, Spaliviero J, Handelsman DJ, Seibel MJ. Perinatal ratio (2D:4D) and birth weight in Nigerians. Anthropologist. 2010; 12: 53. (2D: 4D) as an indicator of body size, testosterone concentration and normal bone remodeling. Am J Physiol Endocrinol Metab. 2006; 290: Klimek M, Galbarczyk A, Nenko I, Alvarado LC, Jasienska G. Digit ratio 71. E456-E462. 523. Vanderschueren D, Vandenput L, Boonen S, Lindberg MK, Bouillon R, number of children in human males. Ann Hum Biol. 2014; 41: 518- 72. 54. Ohlsson C. Androgens and bone. Endocr Rev. 2004; 25: 389-425. index, waist-to-hip ratio, and waist-to-chest ratio: Their relationships Malas MA, Dogan S, Hilal Evcil E, Desdicioglu K. Fetal development of Fink B, Neave N, Manning JT. Second to fourth digit ratio, body mass 475. the hand, digits and digit ratio (2D:4D). Early Hum Dev. 2006; 82: 469- 73. 55. in heterosexual men and women. Ann Hum Biol. 2003; 30: 728-738. Putz DA, Gaulin SJ, Sporter RJ, McBurney DH. Sex hormones and finger Lutchmaya S, Baron-Cohen S, Raggatt P, Knickmeyer R, Manning JT. 2004; 25: 182-199. 2004; 77: 23-28. length: What does 2D:4D indicate? Evolution and Human Behavior. 2nd to 4th digit ratios, fetal testosterone and estradiol. Early Hum Dev. 74. 56. strength in German and Mizos men: Cross‐cultural evidence for an Zheng Z, Cohn MJ. Developmental basis of sexually dimorphic digit Fink B, Thanzami V, Seydel H, Manning JT. Digit ratio and hand‐grip 16289-16294. ratios. Procedings of the National Academy of the Sciences. 2011; 108: 2006; 18: 776-782. 75. organizing effect of prenatal testosterone on strength. Am J Hum Biol. determined by computer‐assisted analysis are more reliable than 57. thoseAllaway using HC, physical Bloski TG, measurements, Pierson RA, Lujanphotocopies, ME. Digit and ratios printed (2D: scans. 4D) et al. Digit (2D:4D) ratio is associated with muscle mass (MM) and Halil M, Gurel EI, Kuyumcu ME, Karaismailoglu S, Yesil Y, Ozturk ZA, 76. Am J Human Biol. 2009; 21: 365-370. strength (MS) in older adults: Possible effect of in utero androgen 58. exposure. Arch Gerontol Geriatr. 2013; 56: 358-363. Hampson E, Ellis CL, Tenk CM. On the relation between 2D:4D and sex- dimorphic personality traits. Arch Sexual Behav. 2008; 37:133-144. Liana S.E. Hone, Michael E. Mc Cullough. 2D: 4D ratios predict hand J Sexual Med Reprod Health 2: 9 8/9 77. ä 86.

2011;Hell B, 51: P ßler376-380. K. Are occupational interests hormonally influenced? 297-300.Selye H, Bajusz E. Effect of denervation on experimentally induced The 2D:4D-interest nexus. Personality and Individual Differences. changes in the growth of bone and muscle. Am J Physiol. 1958; 192: 78. 87. differentiation. Sexual Development. 2010; 4: 270-284. Genet.Paul SN, 2006; Kato 9: BS, 215-219. Cherkas LF, Andrew T, Spector TD. Heritability of Bertelloni S, Baroncelli G, Mora S. Bone health in disorders of sex the second to fourth digit ratio (2D:4D): A twin study. Twin Res Hum 88. 79. Horstman AM, Dillon EL, Urban RJ, Sheffield-Moore M. The role of Manning JT. The finger book: Sex, behaviour and disease revealed in androgens and estrogens on healthy aging and longevity. J Gerontology 80. the fingers. London: Faber and Faber. 2008. 89. Series A: Biological Sciences and Medical Sciences. 2012. McFadden D, Loehlin JC, Breedlove SM, Lippa RA, Manning JT, Rahman Rochira V, Carani C. Aromatase deficiency in men: A clinical 90. 2005;Q. A reanalysis 34: 341-356. of five studies on sexual orientation and the relative perspective. Nat Rev Endocrinol. 2009; 5: 559-568. length of the 2nd and 4th fingers (the 2D:4D ratio). Arch Sex Behav. 81. Veldhuis JD, Roemmich JN, Richmond EJ, Rogol AD, Lovejoy JC. Endocrine control of body composition in infancy, childhood, and 91. 2006;Trivers 49: R, 150-156.Manning J, Jacobson A. A longitudinal study of digit ratio . Endocrinol Rev. 2005; 26: 114-146. (2D:4D) and other finger ratios in Jamaican children. Hor Behav. strength in relation to training level and testosterone in young male 82. Hö Hansen L, Bangsbo J, Twisk J, Klausen K. Development of muscle

nekopp J. Relationships between digit ratio 2D: 4D and self- 92. soccer players. J Applied Physiol. 1999; 87:1141-1147. reported aggression and risk taking in an online study. Personality Kerr JM, Congeni JA. Anabolic-androgenic steroids: Use and abuse in 83. and Individual Differences. 2011; 51: 77-80. 785. pediatric patients. Pediatric Clinics of North America. 2007; 54: 771- Kemper CJ, Schwerdtfeger A. Comparing indirect methods of digit 93. Firebaugh G, Dorius SF. Trends in global gender inequality. Social 84. ratio (2D:4D) measurement. Am J Hum Biol. 2009; 21: 188-191. Forces. 2010; 88: 1941-1968. (2D:4D) and its relationship with body composition indicators among 94. Majumder J, Bagepally BS. The right hand second to fourth digit ratio 95. Iacobucci D. Mediation analysis. Thousand Springs, CA: Sage. 2008. 85. young population. Asian J Med Sci. 2014; 6:78-84. 77: S34-S41. Manning JT,Taylor RP. Second to fourth digit ratio and male ability in Notelovitz M. Androgen effects on bone and muscle. Fertil Steril. 2002; 2001; 22: 61-69. sport: Implications for sexual selection in humans. Evol Hum Behav.

J Sexual Med Reprod Health 2: 9 9/9