Lower bone mass detected at femoral neck and lumbar spine in lower-weight vs normal-weight small-boned women

Predictors of bone mineral density in african-american and caucasian college-aged women

BACKGROUND

Research regarding risk factors and prevalence of low bone mineral density (BMD) among African-American and Caucasian college-aged women are limited. The objective of this cross-sectional study was to determine if selected predictors of BMD in African-American and Caucasian college-aged women differ by race.

METHODS

A total of 101 local African-American (n=50) and Caucasian (n=51) females, ages 18 to 30 years, were in this study. All data were collected in the Bone Density and Body Composition Laboratory. BMD was measured using DXA technology. Race, family history of osteoporosis, BMI, current physical activity, osteoporosis knowledge, length of time on oral contraceptives, age at menarche and calcium intake were included in the multiple regression analyses with spinal and femoral BMD as dependent variables.

RESULTS

Overall, 38.6% had low spinal BMD and 7.9% had low femoral BMD. BMI (β=0.073, R(2) = .148, P = .001, 95% CI [0.030, 0.116]) and current physical activity (β=0.071, R(2) = .148, P = .017, 95% CI [0.013, 0.129]) were the only variables that were statistically significant in predicting spinal BMD. BMI (β=0.056, R(2) = .13, P = .010, 95% CI [0.014, 0.098]) and current physical activ-ity (β=0.078, R(2) = .13, P = .007, 95% CI [0.022, 0.134]) were also the only varia-bles that were statistically significant in predicting femoral BMD. Race was not a significant predictor of spinal or femoral BMD.

CONCLUSION

It is imperative for both African-American and Caucasian women to engage in osteoporosis-preventive behaviors.

Eating Restraint Is Negatively Associated with Biomarkers of Bone Turnover but Not Measurements of Bone Mineral Density in Young Women

Relationships among bone mineral density (BMD), bone turnover markers, cortisol, calcium and vitamin D intakes, and cognitive eating restraint score were examined. Sixty-five healthy women, ages 18 to 25 years, had total body, spine, hip, and forearm BMD measured by dual-energy x-ray absorptiometry. Serum osteocalcin, urinary cross-linked N-telopeptide of type I collagen (NTx), and salivary cortisol were measured, and intakes of calcium and vitamin D were estimated from questionnaires. Cognitive eating restraint scores were determined from the Eating Inventory. Associations between measures were analyzed by Pearson correlations; predictors of BMD and bone turnover markers were tested using stepwise regression. Serum osteocalcin (P<0.01) and urinary NTx (P<0.05) were negatively related to cognitive eating restraint score. Intakes of calcium (P<0.05) and vitamin D (P<0.05) were associated with forearm BMD. Regression analyses indicated that vitamin D intake predicted total body (P<0.08) and forearm (P<0.01) BMD. Negative associations between cognitive eating restraint score and bone biomarkers suggest a reduction in bone remodeling, not reflected in current BMD.

Caloric restriction and calcium's effect on bone metabolism and body composition in overweight and obese premenopausal women

Obesity results in numerous preventable deaths and comorbidities. Unfortunately, a reduction of body weight has been correlated with a reduction in bone mass, the reasons for which have not been fully elucidated. The importance of maximizing peak bone mass during premenopausal years is well known. Most studies demonstrate a positive relationship between calcium intake and bone mass. However, during caloric restriction, which is commonly used for weight loss, calcium intake has shown mixed results. Calcium from dairy sources has received additional attention, beyond its importance to bone, for its role in regulating body weight and composition. Dairy foods are perceived as high fat, and therefore, are generally minimized or avoided during caloric restriction. The current calcium intake for premenopausal women is significantly below recommendations, and even if met during caloric restriction, may not be adequate. This review underscores the need for maintaining at least adequate intake levels of calcium, if not more, during weight loss regimens to minimize potential long-term detrimental effects on bone metabolism.