Association of circulating leptin with bone mineral density in males and females.

Leptin, a hormone produced by fat cells, possesses several physiological functions not limited to energy balance. Recently, leptin has been shown to inhibit bone formation through its action at the hypothalamus. In the present study, the authors explored the association of leptin with bone mineral density (BMD) in men and women according to menopausal status. Subjects consisted of 75 men, 51 premenopausal women and 63 postmenopausal women aged 20-80 years. All were healthy and did not take medication which may affect bone metabolism. BMD was measured at L2-4 and femoral neck by DEXA. Serum leptin concentrations were measured by radioimmunoassay. Serum leptin in males was independently related to BMD at L2-4 (r = -0.36, p < 0.05) and the femoral neck (r = -0.32, p < 0.05) in a multiple linear regression model with age, body mass index (BMI), serum free testosterone, estradiol and leptin as independent variables. In premenopausal women, serum leptin correlated negatively to L2-4 (r = -0.29, p < 0.01) and femoral neck BMD (r = -0.29, p < 0.05) independently of age and BMI. However, in postmenopausal women, no association of leptin with BMD was found after controlling for age and BMI. The authors concluded that circulating leptin is negatively associated with BMD in men and premenopausal women, but not in postmenopausal women. The negative associations found in both premenopausal women and men in the present study strengthen the notion that leptin may inhibit bone formation during the accumulation of bone mass early in life

Influence of normal ageing on mechanism of bone loss in women and men in Bangkok.

Age and sex related changes in bone metabolism are of interest in the pathogenesis of osteoporosis. However, most data in the literature were studied in Western countries. In a tropical country, such as Thailand, little is known of vitamin D status and bone remodeling. Thus, the aim of this study was to determine the changes of vitamin D levels and biochemical markers of bone turnover in healthy women and men of various age groups between 20-80 years who were living in Bangkok. From the results, vitamin D levels of various age groups did not alter significantly between men and women except in the sixth decade of women. However, men had higher levels of vitamin D than women. In women, all biochemical markers of bone turnover increased with age, with a sharp increase at the onset of menopause. In contrast, biochemical markers of bone turnover in men gradually declined with advancing age. CONCLUSION: There was no evidence of vitamin D deficiency in the Bangkok population. Women and men showed different age-related changes in bone metabolism.