INTRODUCTION:Although a fragility fracture family history (FFFH+) has repeatedly been shown to be associated with lower bone mineral density (BMD), its relationship to human BMD change is unclear. Animal research, however, documented that different purebred strains within rodent species have wide ranges in rates of bone acquisition during growth as well as in change post-ovariectomy. Our objective was to compare the rate of premenopausal spinal trabecular BMD change between women with and without a general family history of fragility fracture. PARTICIPANTS AND METHODS:Healthy premenopausal community women participated in prospective observational studies at two academic medical research centres: Vancouver, Canada (n = 66) and Munich, Germany (n = 20). The primary outcome was annual spinal BMD change, measured by quantitative computed tomography (QCT). The two studies employed similar methodologies for assessing QCT and FFFH. RESULTS:Volunteer community participants had a mean age of 36.0 (SD, 6.9) years, body mass index 22.5 (2.4) and baseline QCT of 150.2 (22.5) mg/cm3 trabecular bone. The rates of BMD change were similar in both cities: - 3.5 (5.1)/year Vancouver, - 2.0 (3.4)/year Munich (95 % CI of difference: - 3.9, 0.9). Over a third of the women (31 of the 86, 36 %) reported FFFH+. Those with and without a FFFH were similar in demographics, nutrition, exercise, menstrual cycle and luteal phase lengths and physiological measures (serum calcium, osteocalcin and estradiol). However, women with FFFH+ lost trabecular BMD more rapidly: FFFH+, - 4.9 (5.0), FFFH-, - 2.2 (4.4) mg/cm3/year (95 % CI diff - 0.7 to - 4.8, F1.83 = 7.88, p = 0.006). FFFH+ explained 7.7 % of the variance in QCT volumetric trabecular spinal bone change/year in these healthy premenopausal women. CONCLUSION:This study shows for the first time that having a history of a fragility fracture in a family member is associated with a greater rate of premenopausal spinal trabecular bone loss.

Objective: The purpose was to explore cyclicity of breast tenderness and vasomotor symptoms in menstruating mid-life women using the Daily Perimenopause Diary. Methods: Untreated mid-life women from a convenience sample completed the Daily Perimenopause Diary for clinical (n = 14) or research (n = 10) assessments. Breast tenderness, sleep disturbance and day and night vasomotor intensity were rated on a 0-4 scale with vasomotor number as a count. Daily oral temperature data were analyzed using the Quantitative Basal Temperature algorithm to assess ovulation and estimate luteal phase length. Analysis of variance tested cyclicity using the mean of three 3-day windows (during flow, at mid-cycle and premenstrually). Results: Ninety-eight complete flow-to-flow diaries (from 24 women, mean age 47 years, cycle length 27 ± 6.4 (standard deviation) days) were available, with quantitative temperature data for 60 cycles in 16 women. Of assessed cycles, 90% were ovulatory; 25% had luteal phases < 10 days. Breast tenderness was maximal in the premenstrual window overall (p < 0.0001) and in the ovulatory subset. Night sweats were maximal premenstrually (p = 0.0035) except in anovulatory cycles. Daytime flushes were not cyclic (p = 0.1333) except in ovulatory cycles (p = 0.031). Conclusion: Daily Perimenopause Diaries from mid-life women show premenstrual increases in breast tenderness and night sweats.

BACKGROUND:Positive and negative effects on bone mineral density (BMD) have been described as a result of the premenopausal use of oral contraceptives (OCs); increased fracture rates have also been reported. This study assessed the relation between OC use and BMD in a population-based, 9-centre, national sample of women aged 25-45 years.METHODS:Premenopausal women who had been enrolled in the Canadian Multicentre Osteoporosis Study were classified as having ever been OC users (> or = 3 months) or as having never been OC users (0 to < 3 months). Data were obtained through extensive questionnaires and measuring of participants' weight, height and the BMD of lumbar vertebrae and the proximal femur.RESULTS:Of the sample of 524 women, whose mean age was 36.3 (standard deviation [SD] 5.9) years, 454 had used OCs; their mean age when they started using OCs was 19.8 (SD 3.5) years and the mean duration of use was 6.8 (SD 4.8) years. Women who had ever and those who had never used OCs showed no differences in age, age at menarche, parity, current calcium intake, exercise, body mass index (BMI), education, past irregular cycles or amenorrhea. OC users reported more alcohol and cigarette use and more use of medications to create regular cycles. Mean BMD values (adjusted for age, BMI and height) were 0.02-0.04 g/cm2 (that is, 2.3%-3.7%) lower in OC users, and were significantly lower in the spine and trochanter. The BMD of the spine in OC users was 1.03 (SD 0.12) g/cm2 versus 1.07 (SD 0.12) g/cm2 (95% confidence interval [CI] of difference -0.07 to -0.001) in those who had never used OCs. BMD was neither related to the duration of OC use nor to gynecological age at first use. Current and past users had similar BMD values.INTERPRETATION:National, population-based data show lower BMD values for the trochanter and spine in premenopausal women who have used OCs compared with those who have never used OCs.

To the Editor: In their recent article, “Characterization of Perimenopausal Bone Loss,” Recker and colleagues present unique longitudinal bone mineral density (BMD) and hormonal data.1 We acknowledge the work involved in recruiting, motivating, and continuing to follow 75 women each for an average of 8 years. The data from this study are an important contribution to our knowledge of bone changes through the natural perimenopausal transition. Unfortunately, these authors have chosen to reduce the complex endocrinological and physiological changes of perimenopause2 to one idea—“estrogen deprivation.” Our first concern is that “estrogen deprivation” or “depletion” is not an adequate concept with which to explain the rapid bone loss during perimenopause. The author's own data show that 50% of spinal BMD loss has occurred by 6 months before the final menstrual period at which time estradiol levels are not lower than in the so called “estrogen replete” group. In this study, perimenopausal bone loss appears to begin approximately 3 years before the final menstrual flow, which is about the time when menstrual cycles become irregular.3 Several other studies also show accelerated rates of perimenopausal bone loss.2, 4, 5 During these later phases of perimenopause, estradiol levels can be very high and certainly are not consistently low.2, 6, 7 If estradiol levels are not low in perimenopause, how can we explain the rapid bone loss? First, estradiol levels vary widely.2 Perhaps, acute drops in estradiol levels (often from abnormally high values) cause increased bone resorption much like that which has been shown to occur within seven days of premenopausal ovariectomy.8 A second possibility is that perimenopause causes psychosocial stress.9 Social stress coupled with high estradiol levels in men have been experimentally shown to cause increased cortisol levels10 that are known to be negative for bone. Finally, ovulatory changes that increase as women progress through perimenopause,11 are associated with accelerated cancellous bone loss, despite normal estradiol levels and regular cycles in premenopausal women.12 Replacement of luteal phases with cyclic progestin in a double-blind randomized study in premenopausal women with abnormal cycles caused an important positive change in spinal BMD.13 As a mechanism to allow use of all of their data, the authors labeled “estrogen replete” those women who continued to menstruate as well as those who started hormone therapy before menopause. It seems odd to us to combine data from three women who have undergone ovariectomy and seven women on exogenous hormone therapy with 10 pre- or perimenopausal women. The estrogen deprivation hypothesis has led the authors to overlook important physiological differences within this group. We request that the data for the 10 untreated pre- or perimenopausal women be provided and that we be told whether or not they continued to menstruate regularly. In women's life cycle, low levels of estrogen are as natural for menopausal women as for toddlers. To label menopause as a hormone deficiency condition is to ignore the normal hormonal pattern of women's lives. Recker and colleagues suggest that “hormone replacement therapy” should “begin as early as 2 years before the last menstrual period.” Although we acknowledge that vasomotor symptoms commonly begin in perimenopause and have a very negative impact on quality of life, we suggest that progesterone would be a more appropriate therapy. Progesterone is truly low at this phase of perimenopause11 and is effective for night sweats/hot flushes. We fear that prescription of estrogen to women in late perimenopause may have negative consequences in both the short and the long-term. In the short term, it may exacerbate symptoms such as breast tenderness, headaches, and fluid retention. In the long term, having experienced side effects from estrogen treatment these women may refuse it when they are menopausal, a time when it has the potential to be valuable therapy. In summary, this important study is flawed because it relies on a clearly inadequate “estrogen deprivation” concept as the sole explanation for differences found in the prospective data from midlife women.

This 2-year prospective study examined associations among bone mineral acquisition and physical, maturational, and lifestyle variables during the pubertal transition in healthy girls. Forty-five girls, initially 10.5+/-0.6 years, participated. Body composition and bone mineral content (BMC) at the spine and total body (TB) were assessed at baseline and annually thereafter using dual-energy X-ray absorptiometry (DXA). Nutrient intakes were assessed using 3-day diet records and a calcium food frequency questionnaire (FFQ), physical activity by questionnaire, sexual maturation using Tanner's stages of breast and pubic hair maturation, growth by height and weight, and eating attitudes using the children's Eating Attitudes Test (Children's EAT). Mean children's EAT subscale scores (dieting, oral control [OC], and bulimia) were stable over time. Median split of OC subscale scores was used to form high and low OC groups. Groups had similar body composition, dietary intake, activity, and Tanner stage at baseline and 2 years. Using height, weight, and Tanner breast stage as covariates, girls with low OC scores had greater TB BMC at baseline (1452+/-221 g vs. 1387+/-197 g; p = 0.030) and 2 years (2003+/-323 g vs. 1909+/-299 g; p = 0.049) and greater lumbar spine (LS) BMC at 2 years (45.2+/-8.8 g vs. 41.2+/-9.6 g; p = 0.042). In multiple regression analysis, OC score predicted baseline, 2 years, and 2-year change in TB and spinal BMC, contributing 0.9-7.6% to explained variance. Calcium intake predicted baseline, 2 years, and 2-year change in TB BMC, explaining 1.6-5.3% of variance. We conclude that both OC and habitual calcium intake may influence bone mineral acquisition.

the editor:Two years after the cloning of the second estrogen receptor, ER-␤, the primary sequence encoding the N-terminus of the protein still remains uncertain.The demonstrated importance of estrogen signalling in normal and abnormal development of multiple tissues justifies characterization of this region.Estrogens, involved in the normal development of a wide tissue spectrum including breast, uterus, brain, and bone, are also implicated in several diseases such as breast and endometrial cancers and osteoporosis.In 1995, the cloning (1) of ER-␤ from a rat prostate cDNA library, led to the need to fully re-evaluate estrogen signalling in target tissues.Like estrogen receptor ␣ (2), rER-␤ is a ligand-dependent transcription factor that binds estrogen and antiestrogen.Relying on the presence of an in-frame stop codon upstream of their coding sequence, Kuiper et al.(1) considered their open reading frame to encode the full length protein (R1, Fig. 1).Shortly thereafter, a human homologue, hER-␤, was cloned (3) from testis (H1, Fig. 1).This cDNA encoded a protein 8 amino-acids shorter than rER-␤.In 1997, the hER-␤ cDNA sequence was extended (4) to a start codon corresponding to the first rat methionine codon (H2, Fig. 1), and the mouse homologue, mER-␤, was cloned (5) (M1, Fig. 1).In 1998, following cDNA library screening and/or polymerase chain reaction, the N-terminus of ER-␤ was extended in all three species.Ogawa et al. (6) isolated from human testis a hER-␤ cDNA that could encode 45 additional amino-acids (H3, Fig. 1).This sequence plus the presence of an upstream in-frame stop codon was recently confirmed by Moore et al. (7).In April 1998, a prostate rER-␤ cDNA sequence was submitted to Genbank, that differs from the initial sequence by only one base upstream of the start codon.This extra base alters frame and removes the previously observed in-frame stop codon, resulting in a cDNA that could encode 64 additional N-terminal amino-acids (R2, Fig. 1).In May 1998, two sequences submitted to Genbank extended the initial 5Ј-extremity of the mER-␤ cDNA.The encoded mER-␤ proteins contain 45 and 64 extra amino-acids N-terminal to M1 (M2 and M3, Fig. 1), respectively.All three species present strong sequence similarities in this N-terminal region, although the rodent open reading frames are 19 amino-acids longer than the human.Altogether, these observations raise important questions.Are cloning strategies and/or tissue/species-specific expression of different forms of ER-␤ responsible for observed discrepancies?Do longer forms of ER-␤, as yet unidentified, exist?If so, how is expression regulated?What are the functions associated with these extra amino-acids?The presence of putative phosphorylation and glycosylation motifs within these additional amino-acid sequences suggest possible regulation of putative function(s).Moreover, because of the demonstrated importance of the N-terminal region in ER-␣, particularly the involvement of the AF-1 domain in hormone independent activation of the receptor (8), the elucidation of the function(s) associated with these new regions is necessary.The majority of functional studies undertaken to date were performed with constructs lacking these N-terminal amino-acids: addressing the above questions is critical to fully understanding the involvement of ER-␤ in estrogen signalling.

Current concepts suggest that normal estrogen levels are necessary for exercise to have an osteogenic effect on bone. In a population of running and sedentary women Prior et al. (NEJM, 1990) have shown that consistent ovulation is necessary to prevent spinal cancellous bone loss. Change in spinal bone mineral density was measured by quantitative computed tomography (QCT) in running and sedentary women over one year, along with prospective documentation of dietary, menstrual cycle, hormonal, and exercise variables. Of the 66 women studied only 12 remained ovulatory throughout the year. Forty-two women were runners of which 6 were consistently ovulatory. We hypothesized that ovulation would interact with an exercise effect on cancellous bone. Analysis of the 42 runners showed an average loss in bone of 1.8%. Luteal phase index (r = 0.509) and average progesterone (r = 0.381) were correlated with change in QCT, but not estrogen, calcium, or any other hormonal, dietary, or morphometric variable. There was a negative association between change in QCT and number of km run/week (r = -0.319). In the 12 consistently ovulatory women, average cancellous bone increased in runners(≈2%) and decreased in nonrunners (N) by ≈1% (seefig.). These data are the first to show an increase in purely cancellous bone with moderate levels of aerobic activity. The results suggest that the presence of consistently ovulatory cycles, and thus progesterone in addition to estrogen, may be necessary for an osteogenic effect of low impact exercise (running) on cancellous bone.

The purpose of this study was to contrast the effects of conventional estrogen treatment with medroxyprogesterone on cancellous and cortical bone change in the first year following premenopausal ovariectomy. This 1‐year double‐blind randomized therapy trial was stratified by osteoporosis family history and performed in an academic medical center and community hospitals. Premenopausal women 45 ± 5 years old, postovariectomy for benign diseases were provided 600 mg/day of calcium and randomized to daily therapy with conjugated equine estrogen (CEE, 0.6 mg) or medroxyprogesterone (MPA, 10 mg). The primary outcome variable was spinal quantitative computed tomography (QCT) bone density change over 1 year with additional outcomes of dual‐energy X‐ray absorptiometry (DXA) of proximal femur (FN), whole body (WB), and spine segment (WBS) and N‐telopeptide, bone‐specific alkaline phosphatase, and other bone marker, hormonal, and weight changes. Results in the 33 women completing the study, whose initial bone densities were normal (QCT 133 mg/cm 3 , femoral neck 0.94 g/cm 2 , whole body DXA 1.13 g/cm 2 ), showed annual QCT loss during CEE therapy of −11.5 mg/cm 3 ( p < 0.0007) and MPA bone loss of −19.7 mg/cm 3 ( p < 0.0001). Losses were marginally greater on MPA than CEE ( p = 0.04). Extremely high postovariectomy (5 days) and pretreatment resorption markers (>3 SD above premenopausal normal levels) were significantly related to bone loss. Across the year, resorption decreased during CEE but increased on MPA treatment. Significant DXA bone losses were prevented by CEE treatment (−1.4% FN, −.4% WB, and −1.5% WBS, all NS). However, DXA bone loss was not prevented by MPA treatment (−5% FN, −2.8% WB, and −6.1% WBS, all p < 0.03). Average weight gain was significant (+3.2 ± 4.0 kg) and greater on CEE than MPA (+4.7 vs. +2.0 kg, p = 0.049). In conclusion, CEE therapy did not prevent significant 8% cancellous spinal bone loss in the first year following premenopausal ovariectomy, despite supplementation with 600 mg/day of calcium, good control of vasomotor symptoms, and nearly 5 kg of gain in weight. Significant DXA bone loss, however, was prevented by CEE, but not by MPA therapy. These unexpected results were statistically related to high bone resorption following ovariectomy, which CEE suppressed but MPA did not. Bone formation markers increased during MPA therapy but were unchanged during CEE therapy.

Healthy premenopausal women with regular cycles are believed to be increasing or maintaining bone density. However, few studies have prospectively documented spinal Cancellous bone, the bone that changes rapidly in response to reproductive hormones, in this population. Furthermore, our previous one-year study documented that 24% of the one year bone change by quantitative computed tomography (QCT) was related to subclinical ovulatory disturbances (short luteal phase and non-ovulation) in the presence of regular menstrual cycles. The purpose of this study was to document the Cancellous bone change over five years in this initially ovulatory, premenopausal cohort of 66 healthy women. Thirty-seven women, who continued to be premeno-pausal and have regular cycles, completed this five-year study. Those enrolled differed only by being older and weighing less than those who could not be contacted (n = 19) or who declined to participate (n = 10). Documentation of current ovulatory characteristics was obtained for at least three cycles in 27 women. At the five-year assessment, the volunteers were 40.6 (range 26–47) years old, weighed 58.5 (41–77) kg, and were 160.9 (149–174) cm in height. All were pre-menopausal, healthy, nonsmokers with regular menstrual cycles (mean 27.7, range 24–33 days). Six women with intervenin gevents (such as pregnancy or use of oral contraceptives) had interval (12 to 60 months) QCT changes similar to the remaining 31 (−7.98 vs. −4.92 mg/cm3, 3 p = 0.1, respectively). Mean five-year QCT was 143.0 ± 20.2 mg/cm,3 whereas the initial mean value was 151.9 ± 20.1 mg/cm.3 3 Significant QCT loss over five years (−8.9 ± 6.2 mg/cm3) (95% CI -6.9 to -11.0) correlated with QCT change in the first year (r = 0.629, p < 0.001). First-year change was not related to the subsequent four-year interval change (r = −0.056, p = 0.74), however. Five-year QCT change was not related to age, weight, osteoporosis family history, estimated calcium intake, or exercise, but did correlate with year one luteal index (luteal/cycle length) (r = 0.339, p = 0.043). Significant Cancellous spinal bone loss occurs in healthy, ovulatory premenopausal women, and is influenced by subclinical disturbances of ovulation.

OBJECTIVE:To assess whether temperature is increased by medroxyprogesterone (MPA) and thus whether basal temperature records could be used to determine ovulation during cyclic MPA therapy. DESIGN:A 2-month double-blind placebo-controlled crossover trial in which oral basal temperature was measured daily. SETTING:Normal human volunteers in an academic medical environment. SUBJECTS:Eleven postmenopausal women not taking gonadal hormones. INTERVENTION:Medroxyprogesterone acetate (10 mg/d) or placebo, calendar days 16 to 25, with crossover. MAIN OUTCOME MEASURES:Comparison of mean temperature days 17 to 26 during MPA versus placebo; comparison of differences between temperatures days 7 to 16 and 17 to 26 in MPA versus placebo months; and analysis for a significant monthly thermal shift. RESULTS:The mean temperatures during MPA treatment averaged 0.27 degrees C higher than during the placebo phase and showed a significant change from pretreatment to "treatment" phases during MPA but not during placebo cycles. Eight of the MPA and one of the placebo cycles showed a shift from lower to higher temperatures days 16 to 25. CONCLUSIONS:Medroxyprogesterone acetate has a physiological progesterone-like thermal effect. Therefore basal temperature data cannot reliably indicate ovulation during cyclic MPA administration.

School of Family and Nutritional Sciences and Depts. of Medicine and Radiology, University of British Columbia, Vancouver, Canada.

We assessed the relationship between dietary restraint and menstrual cycle characteristics in 27 ovulatory women, previous participants in a longitudinal study of spinal cancellous bone mineral density (BMD). Subjects completed the restraint scale of the Three Factor Eating Questionnaire, recorded basal temperature and exercise for at least three menstrual cycles, and completed a 3-d food record. Cycle lengths of women in the upper and lower tertiles of scores for restraint were similar [27.8 ± 1.0 (x̄ ± SE) vs 27.6 ± 0.8 d], but luteal phase length was shorter in the former group (8.6 ± 0.9 vs 10.8 ± 0.5 d, P < 0.05). Age, body mass index, percent body fat, waist-hip ratio, reported energy intake, and activity were similar between groups. Because the previous longitudinal study found associations between ovulatory disturbances and bone loss, we assessed spinal BMD using dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT). BMD of women in upper and lower restraint tertiles, respectively, did not differ: DXA, 1.15 ± 0.05 vs 1.20 ± 0.06 g/cm2; and QCT, 140 ± 7 vs 133 ± 7 mg/cm3. Additional prospective studies, however, appear warranted. In conclusion, this study's results provide evidence that high dietary restraint is associated with a shortened luteal phase length.

OBJECTIVE:Bone loss occurs in young women who experience amenorrhea or ovulatory disturbances. The purpose of this study was to determine whether bone loss could be prevented by simulating a more normal hormonal pattern, using treatment with cyclic medroxyprogesterone, with or without calcium supplementation, in physically active women with disturbed menstruation.DESIGN:This study was a 1-year randomized, double-blind, placebo-controlled trial. Women who were stratified by menstrual cycle disturbance were randomized into four groups. The outcome variable was the change in spinal bone density measured by dual energy techniques.SETTING:A large metropolitan area.PARTICIPANTS:Sixty-one healthy, normal-weight physically active premenopausal women aged 21 to 45 years who experienced amenorrhea, oligomenorrhea, anovulation, or short luteal phase cycles completed the study.INTERVENTION:Therapies were cyclic medroxyprogesterone (10 mg/day for 10 days per month) and calcium carbonate (1,000 mg/day of calcium) in four groups: (A) (n = 16) cyclic medroxyprogesterone plus calcium carbonate; (B) (n = 16) cyclic medroxyprogesterone with calcium placebo; (C) (n = 15) placebo medroxyprogesterone with active calcium; or (D) (n = 14) both medroxyprogesterone and calcium placebos.RESULTS:The initial bone density (mean = 1.12 g/cm2) did not differ by group (P = 0.85). The 1-year bone density change was strongly related to treatment with medroxyprogesterone (P = 0.0001) and weakly to calcium (P = 0.072) treatment. Bone density increased significantly (+1.7% +/- 0.5%, +/- SEM, P = 0.004) in the medroxyprogesterone-treated groups (A and B), did not change in the calcium-treated group (C) (-0.7% +/- 0.6%, P = 0.28), and decreased on both placebos (D) (-2.0% +/- 0.6%, P = 0.005).CONCLUSIONS:Cyclic medroxyprogesterone increased spinal bone density in physically active women experiencing amenorrhea or ovulatory disturbances. POTENTIAL CLINICAL SIGNIFICANCE: Amenorrhea, oligomenorrhea, anovulation, and short luteal phase cycles are common in premenopausal women and associated with spinal bone loss occurring at a stage of life when bone density would normally be stable or increasing. This controlled trial shows a significant gain in bone in women in the cyclic medroxyprogesterone intervention group, whereas those subjects in the placebo group lost bone. Calcium supplementation appeared to be helpful but did not reach statistical significance. The implications of these findings for the prevention of osteoporosis warrant further investigation.

A physically active and athletic lifestyle is not only a healthy but a fulfilling choice for women. Although there is extensive literature on 'athletic amenorrhoea' which implies that exercise causes loss of the menstrual cycle, there is inadequate scientific evidence for a causal relationship. The reproductive system adapts to environmental, nutritional, emotional and physical stressors or 'threats' by downward adjustment towards the premenarcheal pattern. The hormonal milieu of this adaptation is low gonadal steroid and high glucocorticoid levels which synergistically increase the risk for a negative bone balance. Athletic women may become amenorrhoeic if reproductive immaturity, emotional stress and undernutrition coexist with increasing exercise loads.Treatment for athletic women with menstrual cycle changes requires that hypothalamic stressors be identified and decreased. In addition, as progesterone deficiency (from disorders of ovulation, whether flow is regular or absent) is the most prevalent menstrual cycle change, treatment with medroxyprogesterone on days 16 to 25 of their cycle will not only provide regular flow (if estrogen levels are sufficient) but will also promote increased bone density.

PRIOR, JERILYNN C.; VIGNA, YVETTE M.; SCHECHTER, MARTIN T.; BURGESS, ARTHUR E. Author Information

BACKGROUND:Osteoporosis develops in women with estrogen deficiency and amenorrhea who lose bone at an accelerated rate. It is not known to what extent bone loss differs between ovulatory women with regular menstrual cycles who are training intensely and those who are sedentary.METHODS:We measured the density of cancellous spinal bone from the 12th thoracic vertebra to the 3rd lumbar vertebra by quantitative computed tomography on two occasions one year apart in 66 premenopausal women 21 to 42 years of age. All the women had two consecutive ovulatory cycles immediately before entering the study. Twenty-one women were training for a marathon, 22 ran regularly but less intensively, and 23 had normal levels of activity. The lengths of the women's menstrual cycles and luteal phases, diet, exercise levels, and hormonal levels were also determined. We defined ovulatory disturbances as anovulatory cycles and cycles with short luteal phases.RESULTS:The mean (+/- SD) spinal bone density in the 66 women decreased 3.0 +/- 4.8 mg per cubic centimeter per year (2.0 percent per year) (P less than 0.001). Amenorrhea did not develop in any woman during the year of observation (only 2.7 percent of the cycles were greater than 36 days long). Ovulatory disturbances occurred in 29 percent of all cycles, however. Bone loss was strongly associated with these disturbances (r = 0.54, 24 percent of the variance). The 13 women who had anovulatory cycles lost bone mineral at a rate of 6.4 +/- 3.8 mg per cubic centimeter per year (4.2 percent per year). The women training for a marathon had menstrual cycles similar to those of the women in the other two groups.CONCLUSION:Decreases in spinal bone density among women with differing exercise habits correlated with asymptomatic disturbances of ovulation (without amenorrhea) and not with physical activity.

Basal temperature data are known to provide unreliable assessments of luteal phase length when they are evaluated by qualitative, visual-pattern methods. This study of 24 cycles in 24 women compared the serum LH peak day with the luteal phase onset day determined by three quantitative basal temperature methods: a) a new computerized least mean square method developed by the authors; b) the mean temperature method reported by Vollman; and c) a computerized version of the World Health Organization cumulative sum method of Royston. The luteal phase onset day determined by the three quantitative basal temperature methods, (a, b, and c) correlated well with the midcycle LH peak (r = 0.879, 0.891, and 0.791, respectively, all p less than 0.001). The cumulative sum method, however, was only able to analyze 19/24 cycles. The mean delay between the LH peak day and the luteal phase onset day determined by thermal shift was 2.4 +/- 1.5, 2.7 +/- 1.4, and 4.1 +/- 2.0 d (mean +/- SD), respectively. The mean temperature method, but not the other two methods, showed an increasing delay between the LH peak day and the thermal shift day with longer follicular phase lengths. Rectal and oral temperature data from the same cycle give identical luteal onset days when analyzed by the least mean square and mean temperature methods, but discrepant days by the cumulative sum analysis. The least mean square technique is a reliable and precise method for population documentation of luteal phase lengths.