Seasonal Variation of Serum Vitamin D Among Greek Female Patients with Osteoporosis

in vivo 29: 409-414 (2015)

GEORGIOS PAPADAKIS1, IOANNIS KERAMIDAS1, KASSIANI KAKAVA2, THEODORA PAPPA1, VASSILIKI VILLIOTOU3, ELENI TRIANTAFILLOU1, ASPASIA DROSOU1, ATHANASIA TERTIPI1, VICTORIA KALTZIDOU1 and ANASTASIOS PAPPAS1

Departments of 1Endocrinology, 2Otolaryngology and 3Biochemical Department, Anticancer Hospital of Piraeus “Metaxa”, Piraeus, Greece

Abstract. Background/Aim: Vitamin D (vitD) levels are solar radiation (14). Accordingly, season (14-16), time of positively associated with bone health and seasonality affects day, sun exposure duration, atmospheric pollution (17), type serum vit D. The aim of the study was to investigate the degree of clothing and sunscreens' interference (SFP and way of of seasonal variation on 25-hydroxyvitamin D (25(OH)D) application) influence its synthesis (12, 13). serum levels in a population-based cohort of post-menopausal The aim of the study was to examine the degree of women with osteoporosis. Patients and Methods: Serum levels seasonal variation of 25(OH)D serum levels, which represent of 25(OH)D were assessed in 596 patients (mean age=65.3 the vitamin D (vitD) status in a population-based cohort of years; standard deviation (SD)=9.4) in different time points female patients evaluated at the Endocrinology Department over a period of 2.5 years. Results: The minimum 25(OH)D for diagnosis and treatment of osteoporosis of the Anticancer serum levels were observed in March (13.4±9.5 ng/ml) and the Hospital of Piraeus “Metaxa”, Piraeus, Greece. maximum levels in August, September and October (29.1±16.1, 28.9±12 and 28.4±8.9 ng/ml, respectively). The Patients and Methods prevalence of vitD deficiency, insufficiency and sufficiency in March was 76.5, 15.7 and 7.8%, respectively. On the contrary, Between August 2012 and December 2014, a total of 596 Greek the highest prevalence of vitD sufficiency was observed in Caucasian female patients were admitted to the Endocrinology August, September and October (38.1%, 45.3% and 46.5%, Department for osteoporosis management. All women, living in Athens for at least 5 years, were postmenopausal and over 46 years respectively). Conclusion: Seasonal variations should be old . Total hip bone mineral density was measured by dual-energy considered when measuring for 25(OH)D serum levels and X-ray absorptiometry and all women had a T-score of -2.5 or less. treating vitD deficiency. Each subject contributed one blood sample during the observation period. All women were on osteoporosis medication prescribed 25 hydroxy vitamin D (25(OH)D) vitamin levels are already by external physicians, including antiresorptive drugs in the positively associated with bone mineral density (1) and form of biphosphonates or denosumab and vitD supplements as several studies have reported a link with muscle mass and multivitamin tablet or as Calcium carbonate with vitD chewable tablet. They had been also advised to expose parts of their bodies strength (2). Additionally, probable associations with type-2 without sunscreen to sunlight for five to ten minutes every day diabetes mellitus (3, 4), certain types of cancer (5, 6), between 10 am and 3 pm in spring, summer and autumn (18). infections (7), autoimmune diseases (8) and cardiovascular The prevalence of 25(OH)D deficiency (<20 ng/ml), insufficiency disease (9) have been described. 25(OH)D levels vary with (20-30 ng/ml) and sufficiency (≥30 ng/ml), as described by the age (10), obesity (11), skin phototype (12), liver and kidney Endocrine Society Clinical Practice guidelines (18), was estimated disease, medication, nutritional habits and others (13). Solar for each month. The analytical assay for the estimation of total radiation is closely related to serum 25(OH)D levels. 25(OH)D was obtained by Roche electrochemiluminescence immuno assay (ECL) on Elecsys and Cobas immunoassay Variations in daylight throughout the year and zenith angle, analyzers. Data were analyzed using the SPSS analytical software depending on the latitude of residence, influence ultraviolet 22 (SPSS Inc – IBM Corporation, New York, United States). The study was approved by the scientific committee of our hospital.

Results Correspondence to: Georgios Papadakis, Anticancer Hospital of Piraeus “Metaxa”, Botasi 51, Piraeus 18537, Greece. Mobile: +30 6932598392, e-mail: [email protected] The study population consisted of 596 osteoporotic postmenopausal women, (mean age=65.3 years (standard Key Words: osteoporosis, vitamin D, seasonal variation. deviation (SD)=9.4, range=46-92 years) with measurements

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Figure 1. Monthly mean levels of 25(OH)D in ng/ml. CI, Confidence interval; 25(OH)D, 25 hydroxy vitamin D.

of 25(OH)D serum levels. The mean age and number of Table I. Mean age (in years) and standard deviation and number of patients assessed every month is shown in Table I. The patients evaluated each month. average 25(OH)D serum level was 21.7 ng/ml (SD=11.67 Month N Mean Std. deviation ng/ml). The monthly mean values of 25(OH)D are presented in Figure 1 and the monthly prevalence of 25(OH)D Jan 28 65.36 8.425 deficiency (serum 25(OH)D <20 ng/ml), insufficiency (serum Feb 51 65.61 8.766 25(OH)D=20-30 ng/ml) and sufficiency (serum 25(OH)D Mar 51 64.04 9.232 ≥30 ng/ml) are presented in histograms in Figure 2. Apr 43 67.44 8.492 May 55 63.58 8.595 The lowest value of 25(OH)D was in March (13.4±9.5 ng/ml) Jun 74 65.27 10.411 and the highest values in August, September and October Jul 60 65.10 9.770 (29.1±16.1, 28.9±12 and 28.4±8.9 ng/ml, respectively). The Aug 42 66.69 9.496 prevalence of 25(OH)D deficiency, insufficiency and sufficiency Sep 53 66.83 8.608 in March was 76.5, 15.7 and 7.8%, respectively. On the other Oct 43 64.81 9.570 Nov 47 65.70 9.982 hand, the highest percentage of patients with 25(OH)D Dec 49 64.22 10.664 sufficiency (38.1%, 45.3% and 46.5%, respectively) were Total 596 65.34 9.416 observed in August, September and October. There was no significant difference in 25(OH)D levels between patients younger than 65 years old and older than Discussion 65 years old. In detail, patients ≤65 years old (n=302) had a mean 25(OH)D=22.3 ng/ml (SD=11.3) and older patients VitD is absolutely essential for the maintenance of healthy (n=294) had a mean 25(OH)D=21.0 ng/ml (SD=11.9); skeleton during our lives. There exists evidence that vitD p=0.47. insufficiency and vitD deficiency in elderly people, and

410 Papadakis et al: Season and VitD in Greece

Figure 2. Monthly prevalence of 25(OH)D status (deficiency, insufficiency and sufficiency).

especially women, leads to secondary hyperparathyroidism Exposure to sunlight results in more sustained levels of and, consequently, to increased bone turnover and finally available 25(OH)D in comparison to the orally-administrated bone loss (19). It is the casual exposure to sunlight that vitD (23). Any excess of vitD produced can be stored in the provides most humans with vitD requirements. Seasonal body fat and used during the winter when little vitD is changes can substantially influence the cutaneous production produced in the skin (22). This is why the levels are higher of vitD. Season at latitudes above or below approximately in October when there is still significant sunlight and the fat 33˚ has to be considered as UVB (280-320 nm) intensity stores are replete after the summer months. On the contrary, decreases during the winter months affecting skin vitD the levels are minimal in March, after wintertime, when it synthesis (20-22). The results of the study show a strong may be preferred to assess serum 25(OH)D levels. This relation between season for a given latitude higher than the could be attributed to sub-optimal medication adherence tropics (Athens, Greece: 37.9˚ north of the equator) and and/or inadequate therapy in combination with the minimal 25(OH)D serum levels. This is why we observe the lowest cutaneous production and depleted adipose tissue stores. levels during winter and the first months of spring. Greece extends between the 34˚ and 42˚ latitudes and the It is possible that a patient with sufficient 25(OH)D serum climate is generally typical of the Mediterranean region with levels at the end of summer may be deficient at the end of mild and rainy winters, relatively warm and dry summers winter. In our study, there was a decrease in 25(OH)D serum and plenty of sunshine throughout most of the year (24). In levels of almost 54% from August to March. These monthly climatological terms, the year can be divided into two main patterns are similar to the results of other studies conducted seasons: The cold and rainy period lasting from mid-October in Germany and Ireland (15, 16), countries located at higher until the end of March and the warm and dry season lasting latitudes than Greece. from April to October. Rainfall, even during the winter

411 in vivo 29: 409-414 (2015) season, does not last for many days and the sky does not this disease (29). This is by far the largest sample-size study remain cloudy for too long. Winter storms are often to date for examining the seasonality of vitD levels in Greek interrupted during January and the first days of February by post-menopausal women with osteoporosis. sunny days, known since antiquity as "halcyon days". Greece is considered a country of high sunlight levels. Accordingly, the weak effect of sunlight for the given Based on the important contribution of sunlight exposure to latitude of Athens could be a possible explanation why serum the production and maintenance of serum 25(OH)D levels, 25(OH)D levels are higher in February than in January and one might consider that 25(OH)D deficiency may be a March in our study. The minimal exposure of face and hands problem limited to countries located at higher latitudes. -without sunscreen- due to increased outdoor activities might Nevertheless, numerous studies from countries with high promote some vitD synthesis during winter. The warmest sunlight levels have shown that vitD deficiency is a common period is between the last ten days of July and the first of occurrence and a global health problem (30, 31). This August when the average maximum temperature ranges from research shows that the majority of women treated for 29˚C to 35˚C. osteoporosis have vitD insufficiency and deficiency Irrespective of the month measured, the majority of post- throughout most of the year. Although a daily dose of at least menopausal women studied had 25(OH)D serum levels 600-800 IU of Vit D is recommended for persons aged more below the recommended threshold of 30 ng/ml. Many older than 50 years old, the dose should be individualized women avoid sunlight exposure because they are not depending on the vitD status and month measured (18). interested in tanning and follow the recommendations of media and Dermatologic Societies concerning skin cancer Conclusion prevention (25), (26). It is generally accepted that UV radiation is the major etiologic agent in the development of Seasonal variations should be considered when measuring skin cancer, melanoma or non-melanoma (27). and correcting vitamin D serum levels. The halcyon days and The sample of our study represents Greek women the lower latitude of Athens, compared to studies conducted receiving osteoporosis treatment. The data are aggregated in other parts of the world, could augment some vitD and do not permit for analysis by personal medical history, synthesis even in the winter. However, the majority of Greek complete medication of each patient or other covariates, such post-menopausal women with osteoporosis could not reach as type of vitD regimen, multivitamin use, body mass index, sufficient 25(OH)D levels, regardless of type and dose of skin pigmentation, clothing style, place, duration of outdoor vitD supplementation and degree of sun exposure. stay. Use of calcium and vitD supplements is very common among Greek post-menopausal women. VitD supplements References are contained in calcium chewing tablets at a usual dose of 400 IU. Medicines containing vitD at higher doses and 1 Tanzy ME and Camacho PM: Effect of vitamin D therapy on supplementation of vitamin D with multi-vitamin bone turnover markers in postmenopausal women with preparations (1,200 IU and 2,000 IU) that are usually osteoporosis and osteopenia. Endocr Pract 17(6): 873-879, 2011. 2 Rizzoli R, Stevenson JC, Bauer JM, van Loon LJ, Walrand S, prescribed for a couple of months are expensive and not Kanis JA, Cooper C, Brandi ML, Diez-Perez A and Reginster public healthcare insurance-covered. The same is also valid JY: The role of dietary protein and vitamin D in maintaining regarding measurement of serum 25(OH)D levels. musculoskeletal health in postmenopausal women: a consensus Additionally, it was difficult to collect information statement from the European Society for Clinical and Economic regarding the dietary habits of the patients. Vitamin D status Aspects of Osteoporosis and Osteoarthritis (ESCEO). Maturitas can be improved by ingestion of fatty fish and intake of vitD- 79(1): 122-132, 2014. fortified milk or orange juice. A high dietary calcium intake 3 Kampmann U, Mosekilde L, Juhl C, Moller N, Christensen B, Rejnmark L, Wamberg L and Orskov L: Effects of 12 weeks has a vitamin D-sparing effect because it increases the half- high dose vitamin D3 treatment on insulin sensitivity, beta cell life of 25(OH)D (28). In Greece, foods are not fortified with function, and metabolic markers in patients with type 2 diabetes vitamin D and diet seems to be constant throughout the year. and vitamin D insufficiency - a double-blind, randomized, Finally, we only had one spot measurement for each placebo-controlled trial. Metabolism 63(9): 1115-1124, 2014. participant. Over-the-year consecutive measurements would 4 Song Y, Wang L, Pittas AG, Del Gobbo LC, Zhang C, Manson be important and future studies may also consider seasonal JE and Hu FB: Blood 25-hydroxy vitamin D levels and incident range of vitD as a confounding factor, from a clinical and type 2 diabetes: a meta-analysis of prospective studies. Diabetes Care 36(5): 1422-1428, 2013. public health perspective. However, our study has an 5 Wactawski-Wende J, Kotchen JM, Anderson GL, Assaf AR, important strength: we included a large sample of post- Brunner RL, O'Sullivan MJ, Margolis KL, Ockene JK, Phillips menopausal women with osteoporosis, a special population L, Pottern L, Prentice RL, Robbins J, Rohan TE, Sarto GE, with high medical needs. It is important to measure serum Sharma S, Stefanick ML, Van Horn L, Wallace RB, Whitlock E, vitD levels in women with osteoporosis as vitD is related to Bassford T, Beresford SA, Black HR, Bonds DE, Brzyski RG,

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Caan B, Chlebowski RT, Cochrane B, Garland C, Gass M, Hays 18 Holick MF, Binkley NC, Bischoff-Ferrari HA, Gordon CM, J, Heiss G, Hendrix SL, Howard BV, Hsia J, Hubbell FA, Hanley DA, Heaney RP, Murad MH and Weaver CM: Jackson RD, Johnson KC, Judd H, Kooperberg CL, Kuller LH, Evaluation, treatment, and prevention of vitamin D deficiency: LaCroix AZ, Lane DS, Langer RD, Lasser NL, Lewis CE, an Endocrine Society clinical practice guideline. J Clin Limacher MC and Manson JE: Calcium plus vitamin D Endocrinol Metab 96(7): 1911-1930, 2011. supplementation and the risk of colorectal cancer. N Engl J Med 19 Lips P, Duong T, Oleksik A, Black D, Cummings S, Cox D and 354(7): 684-696, 2006. Nickelsen T: A global study of vitamin D status and parathyroid 6 Feldman D, Krishnan AV, Swami S, Giovannucci E and Feldman function in postmenopausal women with osteoporosis: baseline BJ: The role of vitamin D in reducing cancer risk and data from the multiple outcomes of raloxifene evaluation clinical progression. Nat Rev Cancer 14(5): 342-357, 2014. trial. J Clin Endocrinol Metab 86(3): 1212-1221, 2001. 7 Adams JS and Hewison M: Update in vitamin D. J Clin 20 Wacker M and Holick MF: Sunlight and Vitamin D: A global Endocrinol Metab 95(2): 471-478, 2010. perspective for health. Dermatoendocrinol 5(1): 51-108, 2013. 8 Cantorna MT and Mahon BD: Mounting evidence for vitamin D 21 Arabi A, El Rassi R and El-Hajj Fuleihan G: Hypovitaminosis as an environmental factor affecting autoimmune disease D in developing countries-prevalence, risk factors and outcomes. prevalence. Exp Biol Med (Maywood) 229(11): 1136-1142, Nat Rev Endocrinol 6(10): 550-561, 2010. 2004. 22 Holick MF: Sunlight and vitamin D for bone health and 9 Al Mheid I, Patel RS, Tangpricha V and Quyyumi AA: Vitamin prevention of autoimmune diseases, cancers, and cardiovascular D and cardiovascular disease: is the evidence solid? Eur Heart J disease. Am J Clin Nutr 80(6 Suppl): 1678S-1688S, 2004. 34(48): 3691-3698, 2013. 23 Haddad JG, Matsuoka LY, Hollis BW, Hu YZ and Wortsman J: 10 MacLaughlin J and Holick MF: Aging decreases the capacity of Human plasma transport of vitamin D after its endogenous human skin to produce vitamin D3. J Clin Invest 76(4): 1536- synthesis. J Clin Invest 91(6): 2552-2555, 1993. 1538, 1985. 24 HNMS: The climate of Greece. http://wwwhnmsgr/ hnms/greek/ 11 Wortsman J, Matsuoka LY, Chen TC, Lu Z and Holick MF: climatology/climatology_html, 2015. Decreased bioavailability of vitamin D in obesity. Am J Clin 25 http://www.myskincheck.gr/index.asp (in greek accessed Nutr 72(3): 690-693, 2000. 02/03/2015) 12 Gilchrest BA: Sun exposure and vitamin D sufficiency. Am J 26 http://www.edae.gr/info.php (in greek accessed 02/03/2015) Clin Nutr 88(2): 570S-577S, 2008. 27 Narayanan DL, Saladi RN and Fox JL: Ultraviolet radiation and 13 Holick MF: Vitamin D deficiency. N Engl J Med 357(3): 266- skin cancer. Int J Dermatol 49(9): 978-986, 2010. 281, 2007. 28 Lips P, van Schoor NM and de Jongh RT: Diet, sun, and lifestyle 14 Webb AR, Kline L and Holick MF: Influence of season and as determinants of vitamin D status. Ann NY Acad Sci 1317: 92- latitude on the cutaneous synthesis of vitamin D3: exposure to 98, 2014. winter sunlight in Boston and Edmonton will not promote 29 Heaney RP: Long-latency deficiency disease: insights from vitamin D3 synthesis in human skin. J Clin Endocrinol Metab calcium and vitamin D. Am J Clin Nutr 78(5): 912-919, 2003. 67(2): 373-378, 1988. 30 Maeda SS, Kunii IS, Hayashi LF and Lazaretti-Castro M: 15 Klenk J, Rapp K, Denkinger MD, Nagel G, Nikolaus T, Peter R, Increases in summer serum 25-hydroxyvitamin D (25OHD) Koenig W, Bohm BO and Rothenbacher D: Seasonality of concentrations in elderly subjects in Sao Paulo, Brazil vary with vitamin D status in older people in Southern Germany: age, gender and ethnicity. BMC Endocr Disord 10: 12, 2010. implications for assessment. Age Ageing 42(3): 404-408, 2013. 31 Levis S, Gomez A, Jimenez C, Veras L, Ma F, Lai S, Hollis B 16 Romero-Ortuno R, Cogan L, Browne J, Healy M, Casey MC, and Roos BA: Vitamin d deficiency and seasonal variation in an Cunningham C, Walsh JB and Kenny RA: Seasonal variation of adult South Florida population. J Clin Endocrinol Metab 90(3): serum vitamin D and the effect of vitamin D supplementation in 1557-1562, 2005. Irish community-dwelling older people. Age Ageing 40(2): 168- 174, 2011. 17 Holick MF: Environmental factors that influence the cutaneous Received March 5, 2015 production of vitamin D. Am J Clin Nutr 61(3 Suppl): 638S- Revised March 13, 2015 645S, 1995. Accepted March 17, 2015

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