Low Back Pain in Japanese Women: Including Cases Caused by Osteoporosis

Ⅵ Low Back Pains

Low Back Pain in Japanese Women: Including cases caused by osteoporosis

JMAJ 46(10): 424–432, 2003

Hiroaki OHTA*, Hiroya OKANO, Yoshiko ONOE, Masazumi YAJIMA, Yuko MIYABARA, Remi YOSHIKATA and Takako MIZUNO

*Professor and Chairman, Department of Obstetrics and Gynecology, Tokyo Women’s Medical University

Abstract: Low back pain is an unavoidable symptom among humans because of their bipedal standing posture and is one of the most common complaints of outpatients. Women, in particular, experience low back pain due to various factors throughout their life cycle. Low back pain can be caused by both physiological and pathological factors, including menstrual pain during puberty, pregnancy and parturition during sexual maturity, vague symptoms during the climacteric, and osteoporosis during old age. These factors lead to a higher prevalence of low back pain in females than in males. This review discusses the roles of anatomical and endocrinological factors in the development of low back pain in women. Apart from low back pain associated with pregnancy, most cases of low back pain due to organic disease in middle-aged and elderly women are related to orthopedic or gynecological conditions. The specific underlying diseases and conditions are reviewed. This article also discusses low back pain related to vague symptoms caused by autonomic disorders. This discussion is based on studies of 400 patients with low back pain. Although there was no significant relation between bone mineral density and the presence or severity of low back pain, we confirmed that vertebral fractures associated with osteoporosis cause symptoms such as low back pain and adversely affect patients’ quality of life. Low back pain is closely related to life style. The close associations with personality and interpersonal relations require that low back pain is comprehensively diagnosed and treated. Key words: Low back pain; Gynecological disease; Indefinite complaint syndrome; Osteoporosis; Bone fracture

Introduction humans have low back pain some time during their lives. Because humans are bipedal and are Irrespective of age and sex, about 80% of subjected to the forces of gravity, the develop-

This article is a revised English version of a paper originally published in the Journal of the Japan Medical Association (Vol. 128, No. 12, 2002, pages 1779–1785). The Japanese text is a transcript of a lecture originally aired on September 19, 2002, by the Nihon Shortwave Broadcasting Co., Ltd., in its regular program “Special Course in Medicine”.

424 JMAJ, October 2003—Vol. 46, No. 10 LOW BACK PAIN INCLUDING OSTEOPOROSIS

ment of low back pain is inevitable. Anatomi- The female pelvis is therefore flat and wide. cally, the head is supported by the neck and These features are important for pregnancy shoulders, the upper body by the thoracic and and parturition, but place muscles and liga- lumbar vertebrae, and the trunk by the knees. ments under considerable physical stress, nec- Increased physical stress that exceeds support essary to maintain balance while walking. This strength can lead to symptoms such as shoulder stress can lead to chronic fatigue and low back stiffness, low and upper back pain, and knee pain. pain. The female pelvis is more complex than the Although both sexes experience low back male pelvis. The uterus, a female organ, and its pain, there are several important distinctions. appendages such as the ovaries and oviducts Females have specific physiological character- have diverse functions. These appendages istics related to pain throughout their life cycle. are suspended from various support systems. From menarche and throughout sexual matu- Relaxation of these systems causes uterine rity, females have considerable menstrual pain, descent and prolapse, which are also associated which may be expressed as low back pain. with low back pain. Pregnancy and parturition are also associated The vaginal orifice is exposed to the external with low back pain. During the climacteric, environment and is contiguous with internal women experience various types of pain, such organs. These anatomic features increase the as headache, shoulder stiffness, low and upper risk of ascending infections. Such infections back pain, knee pain, and lower abdominal cause inflammation, which can spread from pain,1-3) which comprise a constellation of the uterus to surrounding organs and lead symptoms referred to as indefinite complaint to parametritis and related conditions. These syndrome. Older age is associated with an conditions are also potential causes of low back increased risk of osteoporosis. The incidence pain. of osteoporosis is much higher in women than The female pelvis has a well-developed in men.4) Osteoporosis is often initially diag- venous plexus and a vascular system prone to nosed in patients who have low back pain due hyperemia and congestion. Pelvic hyperemia to fractures. and congestion can directly cause low back This article reviews the various causes of low pain.5) The lymphatic system is also well devel- back pain in women. It focuses on low back oped and prone to lymph node swelling. pain caused by gynecological conditions and Lymph node swelling can compress the ner- discusses the role of osteoporosis. vous system, causing low back pain. Tumors of the uterus or ovaries, both benign Causes of Low Back Pain in Females and malignant, that attain a certain size or are located in specific locations can stimulate sur- The incidence of low back pain is far higher rounding nerves and produce low back pain in females than in males. This increased inci- and other symptoms. dence is related to the anatomic and endocrinological characteristics of females. 2. Endocrinologic characteristics Females have hormone cycles controlled 1. Anatomic characteristics mainly by the ovaries and uterus. The menstrual period occurs after the luteal phase of The female pelvis must accommodate a large the ovaries and the secretory phase of the abdominal cavity, required for pregnancy and uterus. Menstrual bleeding occurs with exfoli- parturition. It must also have a distensible and ation of the endometrium. Menstrual pain smooth bony birth canal and soft birth canal. can develop during physiological hormonal

JMAJ, October 2003—Vol. 46, No. 10 425 H. OHTA et al.

Table 1 Causes of Low Back Pain in Middle-Aged and Elderly Women

Gynecological causes 1. Organic causes 1) Positional abnormalities of uterus (uterine descent or prolapse) 2) Uterine tumors (uterine myoma, uterine cancer) 3) Abnormalities of uterine appendages (ovarian tumors) 4) Abnormalities of tissue supporting the uterus (parametritis, etc.) 2. Indeﬁnite complaints caused by autonomic disorders Orthopedic causes Intervertebral disk hernia, spondylosis deformans, spondylolysis, spondylolisthesis, lumbar spinal canal stenosis, osteoporosis, spinal caries, purulent spondylitis, spinal tumors, spinal cord tumors, coccygeal fractures, spinal metastasis from cancer (breast cancer, thyroid cancer, gastric cancer, lung cancer, uterine cancer), so-called lumbago syndrome Urological causes Inﬂammation (pyelonephritis, renal pelvic tumors), calculi, urinary tract obstruction Psychiatric and neurological causes Depression, psychosomatic disease, hypochondria, neurosis Internal and surgical causes Appendicitis, myalgia, neuralgia, rheumatism (From Ohta, H. et al.: Low back pain in middle-aged and elderly women. Obstetrical and Gynecological Therapy 1996; 73: 286Ð292)

changes in the absence of organic disease. aged and elderly women, excluding pregnancy- Endometriosis or uterine myoma can increase related causes, are shown in Table 1.3) The the risk of dysmenorrhea. Changes in various major causes of low back pain are related to organs involved in pregnancy, parturition, and gynecological or orthopedic factors. the puerperium, including alterations of the uterus, pelvic joints, muscles, and ligaments, 1. Positional abnormalities such as uterine can cause low back pain and other symptoms. descent or prolapse During the climacteric, decreased produc- Middle-aged and elderly women often have tion of female hormones, interacting with psy- positional abnormalities of the uterus, such as chic factors and stress, can cause climacteric uterine descent or prolapse. The major symp- symptoms and disturbances. Although hor- toms of this condition include the feeling of an monal changes are not solely responsible for intravaginal or vulvar mass, as well as difficulty indefinite complaints, the indefinite complaints in urination or defecation caused by prolapse associated with the climacteric do not occur in of the bladder and rectum, organs adjacent to the absence of decreased hormone levels. Such the female genital tract. Increased tension on indefinite complaints include low back and ligaments or peritoneum supporting the uterus other types of pain. Endocrinological charac- can produce hypogastric discomfort or abdomi- teristics thus play an important role in the nal pain. Uterine descent usually involves the development of low back pain as well as other vaginal portion of the cervix and is intra- types of pain. vaginal, but can progress to prolapse of the cervix outside the vaginal orifice. Prolapse of Low Back Pain Caused by the uterus can progress further to complete Gynecological Factors uterine prolapse, characterized by downward displacement of the body of the uterus outside Potential causes of low back pain in middle- the vaginal orifice. Chronic prolapse of the

426 JMAJ, October 2003—Vol. 46, No. 10 LOW BACK PAIN INCLUDING OSTEOPOROSIS

uterus can cause hydronephrosis due to com- associated with pain. pression of the urinary tract and passage distur- Advanced ovarian cancers directly invade bances, associated with low back pain. the uterus, ovaries, colorectal region, and ure- Retroflexion of the uterus was previously ters, causing urinary tract disturbances and considered a common cause of low back pain hydronephrosis. Metastasis to bone can cause associated with positional abnormalities of the low back pain. uterus. Corrective surgery was even performed Acute inflammation of uterine appendages, in young infertile women. Currently, however, particularly the oviducts, can cause adnexitis retroflexion of the uterus is not regarded to be with fever and lower abdominal pain. Lower a cause of either low back pain or infertility. back pain also sometimes occurs. When appendages adhere to the posterior surface of the 2. Uterine tumors such as uterine myoma uterus because of chronic inflammation, low and uterine cancer back pain as well as abdominal symptoms such Uterine myoma, a benign tumor arising in as lower abdominal discomfort and abdominal the uterus, is rarely a direct cause of pain fullness sometimes develop. because most myomas arise in the body of the uterus. However, myomas originating in cer- 4. Abnormalities of uterine support tissue, tain locations can produce pain. Subserosal such as parametritis myomas developing in the broad ligament Connective tissue along the uterine cervix is of the uterus (intraligamentous myomas) or referred to as parametrium. Inflammation of myomas arising in the uterine cervix or vaginal this tissue is called parametritis. Along with portion of the cervix can present with low back adnexitis, parametritis is a common inflamma- pain caused by compression of the surrounding tion of intrapelvic organs. Parametritis-related nerves and urinary tract and produce symp- abscesses fill one side of the pelvic category and toms such as feeling of an abdominal mass. compress the uterus, bladder, and colorectum Early uterine cancer is not associated with on the contralateral side, leading to fever as low back or other types of pain, but advanced well as severe lower abdominal pain and low disease with tumor invasion of surrounding tis- back pain. sue and direct stimulation of nerves can cause low back pain and other symptoms. Tumor Low Back Pain as an Indefinite metastasis to the spinal column can produce Complaint Syndrome severe low back pain. Our department surveyed the prevalence 3. Abnormalities of uterine appendages, and severity of low back pain in 400 women such as ovarian tumors attending our climacteric outpatient clinic Ovarian tumors, irrespective of benign or (mean age, 49.2 years; range, 22–80 years) malignant status, present with the features of (Figs. 1–3). These subjects did not include intraligamentous tumors, similar to uterine women with distinct evidence of osteoporosis myomas. Very large tumors can cause abdomi- or gynecological or orthopedic diseases related nal pain as well as low back pain due to com- to low back pain. This survey indicated that pression of surrounding nerves or the urinary about 70% of women in their 30s to 60s have tract. Ovarian tumors may cause torsion, and “low back pain,” irrespective of their specific rupture can produce sudden abdominal and age group. About 35% of these women have low back pain. Torsion can cause tumor necro- severe low back pain interfering with daily sis, and rupture with release of the contents can activities. The prevalence of low back pain result in peritonitis. These conditions are also increases gradually between the ages of 30 and

JMAJ, October 2003—Vol. 46, No. 10 427 H. OHTA et al.

No response 19 (4.8%) 5 28 (23.8%) (30.4%) 33 Pain Mild (35.9%) 21 92 Severe 11 74 (מ) Pain (27.1%) cases cases 5 (52.4%) 95 273 (ם) 400 108 (27.0%) (34.8%) cases 273 cases (23.8%) 31 (68.3%) (33.7%) Moderate 104 (38.1%) 30s 40s

Presence or absence of pain Severity of pain

Fig. 1 Presence or absence and severity of low back pain 26 (22.0%) 5 7 (From Ohta, H. et al.: Low back pain in middle-aged and 43 (26.3%) (36.8%) (36.4%) elderly women. Obstetrical and Gynecological Therapy 1996; 118 19 73: 286Ð292) cases cases 49 7 (41.5%) (36.8%)

50s 60s 2 (33.3%) Severe Moderate Mild 6 15 37 cases cases 22 (40.5%) (59.5%) 4 Fig. 3 Severity of low back pain according to age group (66.7%) (From Ohta, H. et al.: Low back pain in middle-aged and elderly women. Obstetrical and Gynecological Therapy 1996; 73: 286Ð292) 20s 30s

37 48 (30.8%) (22.4%) 39 years and reaches a peak value between 50 156 165 and 59 years. There was no clear-cut difference cases cases 108 128 in disease status among women in their 30s to (69.2%) (77.6%) 50s. However, the prevalence of severe low back pain was lower in women in their 30s than 40s 50s in older women. In conclusion, the prevalence of low back pain was slightly lower and that of severe cases was lower in women in their 30s 10 than in older women. However, there was no (33.3%) remarkable difference in the prevalence or 30 2 cases cases severity of low back pain as compared with 20 women in their 40s to 50s. (66.7%) 2 (100.0%) Low back pain associated with the indeﬁnite complaint syndrome is attributed to fatigue of 60s 70 years or older ligaments and muscles surrounding the spinal cord, caused by activities of daily life. Such Presence Absence symptoms cannot be detected on imaging Fig. 2 Presence or absence of low back pain according to studies or blood tests and are considered tran- age group sient, extremely mild, reversible changes. In (From Ohta, H. et al.: Low back pain in middle-aged and terms of Chinese medicine, fatigue results from elderly women. Obstetrical and Gynecological Therapy 1996; 73: 286Ð292) abnormalities in the distribution of intrapelvic

428 JMAJ, October 2003—Vol. 46, No. 10 LOW BACK PAIN INCLUDING OSTEOPOROSIS

Table 2 Diagnostic Criteria for Pain Disorder (DSM-IV)

A. Pain in one or more anatomical sites is the predominant focus of the clinical presentation and is of sufficient severity to warrant clinical attention. B. The pain causes clinically significant distress or impairment in social, occupational, or other important areas of functioning. C. Psychological factors are judged to have an important role in the onset, severity, exacerbation, or maintenance of the pain. D. The symptom or deficit is not intentionally produced or feigned (as in factitious disorder or malingering). E. The pain is not accounted for by a mood, anxiety, or psychotic disorder and does not meet the criteria for dyspareunia. Code as follows: 307.80 Pain disorder associated with psychological factors: Psychological factors are judged to have the major role in the onset, severity, exacerbation, or maintenance of the pain. (If a general medical condition is present, it does not have a major role in the onset, severity, exacerbation, or maintenance of the pain.) This type of pain disorder is not diagnosed if criteria are also met for somatization disorder. Specify if: Acute : Duration of less than 6 months Chronic: Duration of 6 months or longer 307.89 Pain disorder associated with both psychological factors and a general medical condition: Both psychological factors and a general medical condition are judged to have important roles in the onset, severity, exacerbation, or maintenance of the pain. The associated general medical condition or anatomical site of pain (see below) is coded on Axis III. Specify if: Acute : Duration of less than 6 months Chronic: Duration of 6 months or longer Note: The following is not considered to be a mental disorder and is included here to facilitate differential diagnosis. Pain disorder associated with a general medical condition: A general medical condition has a major role in the onset, severity, exacerbation, or maintenance of the pain. (If psychological factors are present, they are judged not to have a major role in the onset, severity, exacerbation, or maintenance of the pain.) The diagnostic code for the pain is selected based on the associated general medical condition if one has been established (see Appendix G) or on the anatomical location of the pain if the underlying general medical condition is not yet clearly established—for example, low back (724.2), sciatic (724.3), pelvic (625.9), headache (784.0), facial (784.0), chest (786.50), joint (719.40), bone (733.90), abdominal (789.0), breast (611.71), renal (788.0), ear (388.70), eye (379.91), throat (784.1), tooth (525.9), and urinary (788.0). (From Diagnostic and Statistical Manual of Mental Disorders, 4th ed.: DSM-IV. American Psychiatric Association, Washington, D.C., 1994.)

blood flow and reflects “stagnant” blood flow. 4. Low back pain or upper back pain is In addition to such undetectable organic included as a skeletal/muscular symptom changes, indefinite complaints arising from used to evaluate psychosomatic status. so-called autonomic disorders due to climac- 5. About 80% of patients with chronic low teric disturbances may also be involved as psy- back pain are depressed, indicating that chic factors. This assumption is supported by psychic pain is closely related to physical the following five findings: pain. The American Psychiatric Association 1. Low back pain is one of the most common has thus established diagnostic criteria for symptoms of climacteric disturbances.6) chronic pain (physically expressed painful 2. The Kupperman menopausal index,7) long disorders) (Table 2).8) used to diagnose climacteric disturbances These findings strongly suggest that low back and evaluate treatment response, includes pain is related to indefinite complaints caused articular and muscular pain. Low back pain by autonomic disorders. would fall under this category. 3. The classification of autonomic symptoms Low Back Pain and Osteoporosis associated with climacteric disturbances includes low back pain as a sensory and mus- Low back pain has long been considered a cular system symptom. clinical symptom of osteoporosis. Examina-

JMAJ, October 2003—Vol. 46, No. 10 429 H. OHTA et al.

(g/cm2) (g/cm2) (g/cm2) (g/cm2) 1.05 1.05 1.05 1.05 1.00 1.00 1.00 1.00 0.95 0.95 0.95 0.95 0.90 0.90 0.90 0.90 0.85 0.85 0.85 0.85 BMD 0.80 0.80 0.80 0.80 0.75 0.75 0.75 0.75 0.70 0.70 0.70 0.70 0 0 0 0 (ם) Pain (מ) Pain (ם) Pain (מ) Pain (ם) Pain (מ) Pain (ם) Pain (מ) Pain (13 cases) (19 cases) (45 cases) (97 cases) (33 cases)(117 cases) (9 cases) (18 cases) 30s 40s 50s 60s

Fig. 4 Lumbar bone mineral density according to age group. (From Ohta, H. et al.: Low back pain in middle-aged and elderly women. Obstetrical and Gynecological Therapy 1996; 73: 286Ð292)

tions for osteoporosis are done in patients who fractures that are initially diagnosed on radio- have low back pain. However, the World graphic examination are called morphometric Health Organization (WHO) diagnostic crite- fractures. Old fractures are referred to as ria and the Japanese diagnostic criteria for pri- prevalent fractures, and new fractures as inci- mary osteoporosis10–12) do not include the pres- dent fractures. Fractures of the spinal vertebrae ence or absence of low back pain. initially develop in patients in their 50s and We therefore studied whether the presence increase gradually after 70 years of age. The and severity of low back pain are related to lifetime fracture risk in Japanese women is lumbar bone mineral density as assessed by 40%, similar to that in white women. About dual-energy X-ray absorptiometry (DXA) or one-third of women with spinal vertebral frac- to the severity of osteoporosis as evaluated by tures experience pain. Fractures in the other radiographic examination of the spine.3) We two-thirds are asymptomatic and are referred found that the presence of low back pain was to as silent disease.13) not related to either lumbar bone mineral den- The mechanism leading to pain may be sity or to osteoporosis. There was also no sig- direct, with pain occurring at the fracture site, nificant relation between low back pain and or indirect, with pain resulting from fracture- lumbar bone mineral density in any age group related deformity. Progression of osteoporosis (Fig. 4). Similar results were obtained for the leads to more fractures. The development of relation between the severity of low back pain hunchback or humpback is consistently accom- and the level of bone mineral density. These panied by low and upper back pain. Compres- results indicated that low back pain does not sion of the spinal process region induces pain necessarily imply low bone mineral density or a and increases tension on ligaments located diagnosis of osteoporosis (i.e., a risk of osteo- between spinal processes. The site of ligament porosis). Our findings are in accord with the adhesion to bone becomes inflamed, thus caus- diagnostic criteria for osteoporosis proposed ing pain. Hunchback or humpback is associated by the WHO9) and the Japanese Society for with spinal kyphosis. Muscles responsible for Bone and Mineral Research.10–12) extension of the back are therefore constantly Fractures associated with osteoporosis are overextended, concurrently causing fatigue- known to present with low back pain. Fractures induced or ischemic low back pain. Such low accompanied by pain are symptomatic and are back pain is characterized by decreased tension referred to as clinical fractures. Asymptomatic on back muscles on elbow or knee presentation

430 JMAJ, October 2003—Vol. 46, No. 10 LOW BACK PAIN INCLUDING OSTEOPOROSIS

Table 3 Starting Point of Therapy for Osteoporosis Table 5 Decrease in QOL Caused by Osteoporosis-Related (Fracture prevention, particularly of vertebral fractures) Fractures

1. Initial fracture site present QOL 2. Vertebroplastique attempted, but no cure After more After 1 year 3. Disturbance of organ function than 1 year 4. Incidence of osteoporosis-related fractures higher than Healthy adults 1.0000 1.0000 0.1695מ 0.4681מ that in common sites of fracture, such as the femoral neck Femoral neck fracture and distal radius 0.0490מ 0.0502מ *Vertebral fracture 5. Pain frequently delayed 0.0060מ 0.0464מ Distal radius fracture 6. Psychological disadvantages caused by cosmetic problems *Decrease in QOL caused by vertebral fracture is continuous. (From Ohta, H. et al.: Low back pain in middle-aged and elderly women. Obstetrical and Gynecological Therapy1996; 73: 286Ð292) (Modiﬁed from Kanis, J.A. et al.: The burden of osteoporotic fractures: A method for setting intervention thresholds. Osteoporos Int 2001; 12: 417Ð427)

Table 4 Symptoms Associated with Spinal Deformity of symptoms (Table 4) in addition to low and Cervico-omo-brachial syndrome Nervous system: Symptoms mimicking those of cervical upper back pain. Once vertebral fractures spondylosis, drop attacks, cervical vertigo develop, the decrease in the quality of life Muscular system: Chronic cervical pain, brachial pain (QOL) after 1 year is about one-tenth of that Symptoms of low and upper back associated with femoral neck fractures and is Chronic pain and fatigue of long back muscles, gluteal muscles, or tensor fascia lata muscles, nocturnal convul- similar to that associated with distal radius sions of lower extremities fractures. Subsequently, however, the decrease Respiratory symptoms in QOL is one-third of that at 1 year in patients Hypoventilation caused by humpback with femoral neck fractures and two or three- Gastrointestinal symptoms tenths of that at 1 year in patients with distal Chronic reﬂux esophagitis, diaphragmatic hiatal hernia, constipation, ﬂatulence, hemorrhoids, anorexia, vomiting radius fractures. In contrast, QOL does not sub-ileus change appreciably in patients with vertebral Change in appearance fractures. These fractures are thus character- Loss of feminine feeling ized by a trend toward delayed recovery of (From Ohta, H. et al.: Low back pain in middle-aged and elderly QOL (Table 5).14) women. Obstetrical and Gynecological Therapy 1996; 73: 286Ð292)

Concluding Remarks while bending the back posteriorly. Intramus- Low back pain in females can be caused by cular pressure thus decreases and blood flow gynecological diseases as well as by indefinite increases, thereby improving or eliminating complaint syndrome and osteoporosis. Treat- low back pain. ment of low back pain is difficult because Most fractures associated with osteoporosis examinations often reveal no evidence of dis- accompanied by low back pain involve the ease and psychosomatic factors are frequently body of vertebrae. The positioning of vertebral involved. Because there is no single cause, fractures resulting from osteoporosis is shown women who successfully undergo surgery for in Table 3. This table clearly shows the impor- gynecological disease sometimes continue to tance of vertebral body fractures in deciding have pain. Some cases of chronic low back the starting point of treatment for osteoporosis. pain are therefore of unclear etiology and are The development of hunchback or hump- referred to as so-called lumbago syndrome. back requires caution because these conditions Low back pain is closely related to lifestyle can present with an extremely diverse range and can be affected by human and social fac-

JMAJ, October 2003—Vol. 46, No. 10 431 H. OHTA et al.

tors, such as individual personality and inter- 92. (in Japanese) personal relations at home or the workplace. 7) Kupperman, H.S., Blatt, H.M.G., Weisbaden, Low back pain is therefore a condition of H. and Filler, W.: Comparative clinical evalua- modern society. Treatment requires compre- tion of estrogenic preparation by menopausal and amennorheal indices. J Clin Endocrinol hensive assessment of patients including psy- Metab 1953; 13: 688–703. chological factors and living environment as 8) Diagnostic and Statistical Manual of Mental well as clinical symptoms. Providing patients Disorders, 4th ed.: DSM-IV. American Psychi- with support to allow them to understand the atric Association, Washington, D.C., 1994. underlying causes of low back pain is essential (Japanese version: translated by Takahashi, S., for a successful treatment outcome. Ohta, H. and Someya, T., Igaku-Shoin, Ltd., Tokyo, 1996) REFERENCES 9) The WHO Study Group: Assessment of fracture risk and its application to screening for 1) Ohta, H.: Low back pain in menopause: focus postmenopausal osteoporosis. WHO Techni- on its association with menopausal symptoms. cal Report Series, 843, World Health Organiza- The Journal of Therapy 1992; 74: 1260–1267. tion, Geneva, 1994. (in Japanese) 10) Orimo, H.: Diagnostic criteria for primary 2) Ohta, H.: Low back pain in middle-aged and osteoporosis. J of Japanese Society for Bone elderly patients. Obstetrical and Gynecologi- and Mineral Research 1995; 13: 113–118. (in cal Practice 1992; 41: 1671–1676. (in Japanese) Japanese) 3) Ohta, H., Makita, K. and Nozawa, S.: Lum- 11) Orimo, H., Yamamoto, I., Ohta, H. et al.: bago in middle-aged women. Obstetrical and Guidelines for treatment (pharmacotherapy) Gynecological Therapy 1996; 73: 286–292. (in of osteoporosis in Japan. Osteoporos Jpn 1998; Japanese) 6: 203–253. (in Japanese) 4) Ohta, H.: Osteoporosis and hormone replace- 12) Orimo, H.: Diagnostic criteria for primary ment therapy. Sex Difference and Similarity osteoporosis (year 2000 revision). J of Japa- 2002; 8: 18–27. (in Japanese) nese Society for Bone and Mineral Research 5) Ohta, H. and Makita, K.: Low back pain as 2000; 18: 76–84. (in Japanese) gynecologists often associate it as indeﬁnite 13) Ohta, H.: Osteoporosis. Ed. by Sato, K. and complaint in female patients. The Journal of Fujimoto, S. Clinical Evidence-based Gyneco- Therapy 1995; 77: 1646–1657. (in Japanese) logical Science, Medicalview, Tokyo, 2003, 6) Makita, K., Ohta, H., Komukai, S. et al.: Initial pp.306–313. results of an ongoing outpatient health main- 14) Kanis, J.A., Oden, A., Johnell, O. et al.: The tenance program for middle-aged and elderly burden of osteoporotic fractures: A method women—outpatient health maintenance in for setting intervention thresholds. Osteo- women—. J Jpn Menopause Soc 1993; 1: 86– poros Int 2001; 12: 417–427.

432 JMAJ, October 2003—Vol. 46, No. 10