Associations between body morphology and bone mineral density in premenopausal women

To investigate whether body morphology, obesity and its long time evolution were associated with lumbar and femoral bone mineral density (BMD) in premenopausal women of the same age. DESIGN: Cross-sectional study. SUBJECTS: 72 healthy premenopausal women born in 1950 (42 years) with a regular physical activity. MEASUREMENTS: BMD measured by dual-X-ray absorptiometry (DEXA) at lumbar spine and proximal femur; body weight, body mass index (BMI), BMI at 20 years (BMI-20), increase in BMI since age of 20 (BMI->20), body circumferences (breast, waist, hip) and their ratios (WHR, BHR, WBR), smoking and alcohol intake. RESULTS: Lumbar spine BMD did not correlate with any anthropometric measurement. Femoral BMDs correlated positively with weight, BMI, BMI-20, breast, waist, WHR and BHR. The BMI-20 explained the 5% and the current BMI the 13% of variance of total femur BMD. After adjustment for weight or BMI, breast circumference and BHR remained significantly correlated with all femoral BMDs sites except neck. Weight was the best predictor for neck BMD (R2 = 0.08; p < 0.02), and BHR for Ward's triangle (R2 = 0.12; p < 0.01) and trochanter (R2 = 0.10; p < 0.001). Alcohol intake, cigarette smoking, and age of menarche were not related to BMDs. CONCLUSION: In premenopausal women of the same age, lumbar spine BMD was not associated with any anthropometric measurement. Greater BHR and its long time of evolution may be determinants of greater femoral BMD (trabecular), whereas body weight may be determinant of femoral neck BMD (cortical). Further studies are needed to determine whether large breast to hip ratio may be considered as a protective factor for femoral osteoporosis.     

Nutritional influences on bone mineral density: a cross-sectional study in premenopausal women

The association between current and past dietary intake and bone mineral density (BMD) was investigated in 994 healthy premenopausal women aged 45-49 y. BMD was measured with dual-energy X-ray absorptiometry (DXA). Dietary intake was assessed with a food-frequency questionnaire (FFQ). Energy-adjusted nutrient intakes were grouped into quartiles and mean BMD at the lumbar spine (LS), femoral neck (FN), femoral trochanter (FT), and femoral Wards (FW) were calculated. With higher intakes of zinc, magnesium, potassium, and fiber, LS BMD was significantly higher (P < 0.05-0.006), and a significant difference in LS BMD was also found between the lowest and highest quartiles for these nutrients and vitamin C intake (P < 0.05-0.01). These results remained significant after adjustment for important confounding factors. LS BMD and FT BMD were lower in women reporting a low intake of milk and fruit in early adulthood than in women with a medium or high intake (P < 0.01). High, long-term intake of these nutrients may be important to bone health, possibly because of their beneficial effect on acid-base balance.     

Contributions of exercise, body composition, and age to bone mineral density in premenopausal women

The purpose of this cross-sectional study were to determine whether exercisers have greater bone mineral density (BMD) than nonexercisers, whether aerobic dancers have greater BMD than walkers, and to determine the contributions of energy expenditure, body composition, and dietary factors to spine and femur BMD. Measurements were obtained on 93 eumenorrheic women (walkers N = 28; aerobic dancers, N = 34; nonexercisers, N = 31) ages 25-41 yr; lumbar spine and proximal femur BMD, body composition, physical activity, and nutrient intakes. Mean height, weight, and body mass index and median age and calcium intakes were similar for the three groups. Mean (+/- SD) values of the spine, total femur, and femoral neck BMD, respectively, were: walkers (1.092 (+/- 0.098), 0.947 g.cm-2), dancers (1.070 (+/- 0.124), 0.990 (+/- 0.104), 0.908 (+/- 0.106) g.cm-2), and nonexercisers (1.020 (+/- 0.112), 0.887 (+/- 0.073), 0.792 (+/- 0.089) g.cm-2) multiple regression analyses indicated that exercise contributed to spine (P = 0.018), total femur (P =0.012), and femoral neck (P < 0.0001) BMD, whereas type of exercise (aerobic dance vs walking) did not (P > 0.05). Total femoral BMD was influenced by exercise (P = 0.012) and energy expenditure (P = 0.023), while vertebral BMD was influenced by age (P = 0.0067), body weight (P = 0.017), and exercise (P = 0.018). These findings suggest that walking and aerobic dance exercise may provide physically active premenopausal women with greater lumbar and femoral BMD than sedentary females.     

Decreased bone mineral density in premenopausal patients with systemic lupus erythematosus

To study bone mineral density (BMD) in premenopausal adult female patients with systemic lupus erythematosus (SLE) and its relation with clinical parameters, 56 SLE patients (mean age 31 years, mean disease duration 6.3 years) and 15 normal controls were studied. BMD at the lumbar vertebrae (L2-L4) was measured by dual energy X-ray absorptiometry (DEXA). Classification of BMD was made according to the WHO criteria in 1994. Correlation between BMD and clinical parameters was calculated. It was found BMD in the SLE patients (0.942 +/- 0.136 g/cm2) was lower than in the control group (1.055 +/- 0.080 g/cm2) (P < 0.01). According to the WHO criteria, 17 patients (30%) had normal BMD, 22 patients (40%) had osteopenia and 17 patients (30%) had osteoporosis. BMD was inversely correlated with disease duration in SLE patients (p < 0.005). The minimal disease duration for a female SLE patient to develop osteopenia was 3.5 years. In conclusion, SLE patients have lower lumbar BMD than normal controls. SLE patients with longer disease duration have lower BMD. In order to achieve early prevention of osteoporosis, we suggest that female SLE patients with disease duration for more than 3.5 years should take a BMD examination.     

Vitamin D receptor alleles do not correlate with bone mineral density in premenopausal Caucasian women from the southeastern United States

Genetic factors are important in determining peak bone density. Recent studies indicate that polymorphisms of the vitamin D receptor (VDR) may account for much of the genetic contribution to bone density, and VDR genotype may be useful to predict the risk of developing osteoporosis. However, the association between VDR genotype and bone mineral density (BMD) has not been observed in all populations. We determined VDR genotype in 69 healthy premenopausal Caucasion women from the southeastern United States and measured BMD at the lumbar spine (anterior-posterior [AP] and lateral views) and proximal femur. We found no association between VDR genotype and BMD at any site. Our results indicate that in this population, VDR genotype does not predict peak bone density and should not be used to predict the risk of developing osteoporosis.     

Determinants of premenopausal bone mineral density: the interplay of genetic and lifestyle factors

Bone mineral density (BMD) is a reflection of both genetic and lifestyle factors. The interplay of genetic (vitamin D receptor [VDR] gene polymorphisms) and lifestyle factors on BMD at the lumbar spine and proximal femur was examined in 470 healthy premenopausal women, aged 44-50 years, using a Hologic QDR 2000 densitometer. The objective of this study was to examine the genetic and lifestyle determinants of premenopausal BMD. Each participant was genotyped for BsmI polymorphism at the VDR gene locus. The presence of a restriction site within VDR, specified as bb (189, 40.2%) (n, %) was associated with reduced spinal BMD, whereas absence of this site in BB (97, 20.6%) conferred greater spinal BMD, as did the genotype Bb (184, 39.1%). Associations between smoking, alcohol use, oral contraceptives, education level, multivitamins, number of children, degree of obesity, body weight, physical activity, dietary calcium intake, and VDR genotype to BMDs were examined. VDR genotype, body weight, degree of obesity, physical activity, and dietary calcium intake were all significant determinants of BMD. The association of VDR genotype with BMD at the femoral neck appeared to be modified by calcium intake (BB and Bb: 0.797 +/- 0.11 g/cm2 vs. 0.844 +/- 0.11 g/cm2, interaction term, p = 0.06) for low (< 1036 mg/day) and high (> or = 1036 mg/day; upper quartile) calcium intakes, respectively. A similar trend was demonstrated for physical activity. These findings suggest that prophylactic interventions aimed at achieving and maintaining optimal BMD, such as greater calcium intake or physical activity, may be important in maximizing one's genetic potential for BMD.     

Regional bone mineral density interrelationships in normal and osteoporotic postmenopausal women

We describe a prospective study in which bone mineral density (BMD) was measured in total body and regions, proximal femur, lumbar spine, and forearm in 84 apparently normal postmenopausal women with normal spinal radiographs and in 47 women with 1-10 wedged or compressed vertebrae. There was a history of peripheral fracture in 35 of the 84 controls and 30 of the 47 osteoporotics (p < 0.02) but there was no association between vertebral fracture and wrist fracture. At all sites and regions, the differences in BMD between the "normal"and "osteoporotic" women was highly significant and all but "ribs" and "arms" remained significant after correction for menopausal age. In the whole set, and in both subgroups, the coefficients of correlation between sites and regions were all highly significant (p < 0.001). Nonetheless, some sites discriminated better between the two groups than others. Standardized odds ratios (OR) for vertebral fracture versus no-fracture were calculated by logistic regression and expressed as the rise in OR for each standard deviation (SD) fall in bone density. This ratio was greatest (3.4) in "pelvis" and weakest (1.7) in "ribs" but all were statistically significant. Geometric mean regression equations were calculated for all the 78 possible pairs of sites and regions in the 84 normal subjects and the deviations of the osteoporotic women from these normal slopes calculated. In most pairs of sites and regions, the vertebral fracture cases were scattered around the normal group's slope but fell lower down on both axes. The bone deficits in the osteoporotics compared with young normal women ranged from -14% in "head" to -40% in Ward's triangle and the T-scores ranged from -1.9 in "ribs" to -3.9 in the forearm. Sensitivity ranged from 17% in "ribs" to 36.2% in Ward's triangle. Specificity varied between 88 and 94% and the percent correctly classified ranged from 62.6% in "ribs" to 72.5% in Ward's triangle. We conclude that primary postmenopausal osteoporosis affects the entire skeleton but that some sites discriminate better between vertebral fracture and nonfracture cases regardless of whether they represent cortical or trabecular bone.     

Body weight and bone mineral density in postmenopausal women with primary hyperparathyroidism

OBJECTIVE: To assess bone mineral density and body composition in postmenopausal women with primary hyperparathyroidism. DESIGN: Cross-sectional study with an age-matched control group. SETTING: University teaching hospital. PATIENTS: 41 postmenopausal women with mild primary hyperparathyroidism and 43 eucalcemic, age-matched controls. MEASUREMENTS: Total body, lumbar spine, and proximal femoral (femoral neck, Ward's triangle, and trochanter) bone mineral density; body composition; and fat distribution were measured using dual-energy x-ray absorptiometry. RESULTS: Women with primary hyperparathyroidism were heavier (75.5 kg compared with 66.3 kg; difference, 9.2 kg [95% CI, 3.7 to 14.7 kg]; P = 0.002), had a higher fat mass (33.3 kg compared with 26.1 kg; difference, 7.2 kg [CI, 3.0 to 11.4 kg]; P = 0.001), and had a more android pattern of fat distribution (android-to-gynoid fat ratio, 1.05 compared with 0.84; difference, 0.21 [CI, 0.1 to 0.32]; P = 0.0004) than the controls. Unadjusted bone mineral density was similar in patients and controls at all sites: total body, 0.990 compared with 1.023 g/cm2 (difference, 0.033; CI, -0.004 to 0.070); posteroanterior lumbar spine, 1.032 compared with 1.018 g/cm2 (difference, 0.014; CI, -0.031 to 0.059); lateral lumbar spine, 0.569 compared with 0.528 g/cm2 (difference, 0.041; CI, -0.022 to 0.104); femoral neck, 0.799 compared with 0.825 g/cm2 (difference, 0.026; CI, -0.072 to 0.124); Ward's triangle, 0.653 compared with 0.677 g/cm2 (difference, 0.024; CI, -0.035 to 0.089); trochanter, 0.734 compared with 0.733 g/cm2 (difference, 0.001; CI, -0.024 to 0.026); and arms, 0.720 compared with 0.739 g/cm2 (difference, 0.019; CI, -0.015 to 0.053). After adjustment for body weight, bone mineral density in women with primary hyperparathyroidism was lower than that in controls for total body (P = 0.0004), femoral neck (P = 0.001), Ward's triangle (P = 0.01), trochanter (P = 0.02), and arms (P = 0.0006). Spinal bone mineral density did not differ between groups. CONCLUSIONS: Body weight, total body fat mass, and proportion of android fat are increased in postmenopausal women with primary hyperparathyroidism; these unexplained factors may be relevant to the increased incidence of cardiovascular disease in this condition. Unadjusted bone mineral density values are similar in patients with primary hyperparathyroidism and in controls, suggesting that this condition is not associated with an increased risk for fracture.     

Exercise and bone mineral density

A decrease in physical activity may lead to an increased loss of bone and an increase in the incidence of osteoporotic fractures. Studies have demonstrated increases in bone formation in animals and increases in bone mineral density in humans. Studies of animals show that bone has enhanced physical and mechanical properties following periods of increased stress. Strains which are high in rate and magnitude, and of abnormal distribution, but not necessarily long in duration, are best for inducing new bone formation, resulting in the strengthening of bone by increased density. Cross-sectional studies show that athletes, especially those who are strength-trained, have greater bone mineral densities than nonathletes, and that strength, muscle mass and maximal oxygen uptake correlate with bone density. Longitudinal training studies indicate that strength training and high impact endurance training increase bone density. Strain induction, the deformation that occurs in bone under loading, may cause a greater level of formation and an inhibition of resorption within the normal remodelling cycle of bone, or it may cause direct activation of osteoblastic bone formation from the quiescent state. Various mechanisms have been proposed for the transformation of mechanical strain into biochemical stimuli to enhance bone formation. These include prostaglandin release, piezoelectric and streaming potentials, increased bone blood flow, microdamage and hormonally mediated mechanisms. These mechanisms may act on their own or in concert, depending on the loading situation and the characteristics of the bone.     

Nonsteroidal anti-inflammatory drugs and bone mineral density in older women: the Rancho Bernardo study

Nonsteroidal anti-inflammatory drugs (NSAIDs) are known to inhibit synthesis of prostaglandins and may help prevent bone loss, but no study has shown the differential association of type or dose of NSAID compound with bone mineral density (BMD). The purpose of this study was to determine the relation of NSAIDs by type and dose to BMD. Participants were 932 Caucasian, community-dwelling women aged 44-98 years from southern California. Data were collected from 1988 to 1991 through the use of standardized medical questionnaires. Medication use was validated by a nurse. BMD at the ultradistal and midshaft radii were measured using single-photon absorptiometry, and at the hip and lumbar spine using dual-energy X-ray absorptiometry. Women (mean age, 72 years) were classified into 818 nonusers and 114 regular daily users of NSAIDs, of which 84 used propionic acid NSAIDs and the remainder used acetic acid NSAIDs. Occasional NSAID users were excluded. Women who used propionic acid NSAIDs, but not acetic acid NSAIDs, had higher BMD at all five sites and significantly higher BMD at the midshaft radius and lumbar spine. These differences remained after controlling for known covariates of osteoporosis. When women with self-reported osteoarthritis were excluded from the model, significantly higher BMD in propionic acid NSAID users was also observed at the femoral neck and total hip. Those who concurrently used estrogen and propionic acid NSAIDs had the highest BMD at all sites, suggesting an additive effect. We conclude that regular daily use of propionic acid NSAIDs, with or without simultaneous use of estrogen, may be helpful in preventing bone loss in older women. However, further research is needed to confirm these results before any clinical practice guidelines can be recommended due to the increased risk of serious complications associated with NSAID use.     

Peripheral body fat has a protective role on bone mineral density in elderly women

OBJECTIVES: To determine whether bone mineral density is lower in women living in homes for the elderly as compared to free dwelling control subjects, and to investigate factors affecting possible differences. This is the first study with this objective as the primary aim. DESIGN: Case-control study. SUBJECTS AND METHODS: Institutionalised independent elderly women (n = 22, mean age = 75.1 y+/-6.43 s.d.) randomly selected in a home for the elderly and 22 age-matched control women randomly selected from a sample representative of the independent non institutionalised local population who underwent dual energy X-ray absorptiometry (DXA) at the lumbar spine and right femoral neck; anthropometric measurements (height, weight, subscapular and triceps skinfold thickness); general questionnaire. RESULTS: Mean bone mineral density at the femoral neck was 0.618 g/cm2 (+/-0.130s.d.) in institutionalised women and 0.709 g/cm2 (+/-0.106 s.d.) in controls (P = 0.02, t-test). Controlling for confounding factors in the analysis of covariance, triceps skinfold thickness and living in a home for the elderly turned out to be significant determinants of bone mineral density. CONCLUSION: When compared to free dwelling control subjects, institutionalised women show lower bone density, that is the main risk factor for fracture. Reduced peripheral body fat was significantly associated with the low bone mineral density observed. Health programs aimed at decreasing the incidence of fractures among institutionalised subjects will also have to consider the effect of nutritional or life style factors that reduce peripheral body fat.     

Energy expenditure and physical activity in relation to bone mineral density in women with anorexia nervosa

OBJECTIVES: To assess sleeping metabolic rate (SMR), average daily metabolic rate (ADMR), and total bone mineral density (TBMD) in women with anorexia nervosa, and to evaluate the effect of daily physical activity on TBMD. DESIGN: We compared women with anorexia nervosa and controls using measurements on body composition, and energy expenditure. Relations between these measurements were investigated. SETTING: Daily living environments in The Netherlands, and body composition and energy expenditure laboratory of the Department of Human Biology. SUBJECTS: Twelve adult, non-hospitalized women with anorexia nervosa, and sixteen adult normal weight women. INTERVENTIONS: Average daily metabolic rate was measured with the doubly labeled water method and sleeping metabolic rate in a respiration chamber. TBMD was measured by dual energy X-ray absorptiometry, and percentage body fat was calculated combining the results from underwater weighing and deuterium dilution. RESULTS: TBMD was significantly lower in anorexia than in controls (0.989 +/- 0.081 vs 1.144 +/- 0.054 g/cm2). Also ADMR and SMR were reduced in anorexia. The physical activity index (PAI = ADMR/SMR) was not significantly different from PAI in controls. In anorexia, TBMD was related to the PAI (R2 = 0.35, P < 0.05). Finally, stepwise multiple regression revealed that PAI together with the study groups as dummy variables could explain 69% of the variation in TBMD. CONCLUSION: These findings show that in anorexia TBMD is reduced, but that nonetheless physical activity has a significant positive effect on bone density.     

Premature hair graying and bone mineral density

In a recent case-control study, premature hair graying was found to be associated with osteopenia, suggesting that this might be a clinically useful risk factor for osteoporosis. We report a reexamination of this possibility in 293 healthy postmenopausal women. Subjects experiencing onset of hair graying in their 20s tended to have lower bone mineral density throughout the skeleton (adjusted for age and weight) than those with onset of graying later in life. The same was true for those in whom the majority of their hair was gray by the age of 40 yr (n = 16), in whom bone density was reduced by 7% in the femoral neck, 8% in the femoral trochanter, and 4% in the total body (P < 0.05) when compared with those not prematurely gray. Bone density at the lumbar spine and Ward's triangle showed similar trends that were not significant. However, premature hair graying explained only 0.6-1.3% of the variance in bone mineral density within the population. We conclude that premature hair graying is associated with low bone density, but that its infrequency in the normal postmenopausal population leads to its accounting for only a tiny fraction of the variance of bone density.     

Effect of vitamin D receptor gene polymorphism and lifestyle on bone mineral density and bone mineral density decrement rate

The effects of genetic and environmental factors on bone mineral density (BMD) were investigated in 108 healthy Japanese women. Of the 108 subjects, BMD (from the second to forth lumbar vertebrae) was measured in 1992 in 103, in 1993 in 100, and in both years in 95 by dual energy X-ray absorptiometry. Vitamin D receptor (VDR) gene polymorphism in intron 8 was used as a genetic marker. Information on menstruation, health status, lifestyle, quantities of nutrient intake and frequencies of food intake was obtained by questionnaire. The frequency of allele B (825bp), whose polymerase chain reaction (PCR) products cannot be cut with BsmI, was 0.259 and the frequency of allele b (650bp), whose PCR products can be cut with BsmI, was 0.741. The subjects in our study obeyed the Hardy-Weinberg law. While the frequency of allele B was 0.448 in European whites as reported by Morrison et al, it was 0.259 in our Japanese subjects, suggesting a racial difference. Z score values (average value 0, standard deviation 1) increased in the order BB, Bb and bb. This result indicates that allele B is associated with the lower BMD in Japanese, as in European whites. The BMD decrement rate increased in the order bb, Bb and BB, indicating that VDR gene polymorphism may be a regulatory factor for losing BMD. Most of lifestyle variables, calcium intake and vitamin D intake were not correlated with BMD, but the food frequency score (which was defined as values weighted in each of three food categories obtained by factor analysis) was significantly correlated with BMD. Multiple regression analysis showed significant influences of years after menopause, the food frequency score and VDR genotype on BMD. VDR genotype and years after menopause influenced the BMD decrement rate significantly in multiple regression analysis. Neither a relationship between BMD and calcium intake nor between BMD and vitamin D intake by VDR genotype was found. These results suggest that the VDR gene is a genetic factor in BMD and the BMD decrement rate in Japanese.     

Relationship between nutrient intake and bone mineral density in an urban community of healthy elderly women

The relationship between nutrient intake and bone mineral density (BMD) in a community of healthy elderly women was investigated. A three-day nutritional survey was carried out. Subjects were divided into two groups using criteria set by the Recommended Dietary Allowances for the Japanese Fifth Revision (1994). Relationship between nutritional intake and BMD was explored. Intake of energy, protein, fats, and vitamins B1 and B2 correlated positively with BMD, as did the intake of eggs, meat, legume and soya products, other vegetables and potatoes, as well as fat and oil. Those with larger average number of food ingested per day had higher average of BMD. In conclusion, the hypothesis: adequate dietary intake protects against BMD loss, agreed with the results. Sufficient nutrient and food intake is associated with BMD increase, and possibly reduced risk of osteoporosis.     

Calcium supplementation and bone mineral density in adolescent girls

OBJECTIVE: To evaluate the effect of calcium supplementation on bone acquisition in adolescent white girls. DESIGN: A randomized, double-blind, placebo-controlled trial of the effect of 18 months of calcium supplementation on bone density and bone mass. SUBJECTS: Ninety-four girls with a mean age of 11.9 + 0.5 years at study entry. SETTING: University hospital in a small town. INTERVENTIONS: Calcium supplementation, 500 mg/d calcium as calcium citrate malate; controls received placebo pills. MAIN OUTCOME MEASURES: Bone mineral density and bone mineral content of the lumbar spine and total body were measured by dual-energy x-ray absorptiometry and calcium excretion from 24-hour urine specimens. RESULTS: Calcium intake from dietary sources averaged 960 mg/d for the entire study group. The supplemented group received, on average, an additional 354 mg/d of calcium. The supplemented group compared with the placebo group had greater increases of lumbar spine bone density (18.7% vs 15.8%; P = .03), lumbar spine bone mineral content (39.4% vs 34.7%; P = .06), total body bone mineral density (9.6% vs 8.3%; P = .05), and 24-hour urinary calcium excretion (90.4 vs 72.9 mg/d; P = .02), respectively. CONCLUSIONS: Increasing daily calcium intake from 80% of the recommended daily allowance to 110% via supplementation with calcium citrate malate resulted in significant increases in total body and spinal bone density in adolescent girls. The increase of 24 g of bone gain per year among the supplemented group translates to an additional 1.3% skeletal mass per year during adolescent growth, which may provide protection against future osteoporotic fracture.     

Vitamin-D-receptor-gene polymorphisms and change in lumbar-spine bone mineral density

Common vitamin-D-receptor (VDR) gene allelic variants predict bone mineral density. We analysed VDR alleles and rate of change of lumbar-spine bone mineral density over 18 months in 72 elderly subjects. 9 BB homozygotes lost bone mineral density but 26 homozygotes for the alternative genotype (bb) did not (mean change -2.3 [SE 1.0] vs 0.9 [0.7]% per year, p < 0.05), irrespective of calcium intake. Among 37 heterozygotes (Bb), however, change in bone mineral density correlated with calcium intake (r = 0.35, p < 0.03). This association between a genetic marker and rate of bone loss in the elderly suggests that the effect of calcium intake on maintenance of bone mass could relate to VDR gene polymorphisms.