Relationships between bone mass and circulating leptin concentrations in Hutterites

Elevated adiponectin but varied response in circulating leptin levels to falciparum malaria in type 2 diabetics and non-diabetic controls

Background

To investigate effects of falciparum malaria on circulating levels of leptin and adiponectin in type 2 diabetes mellitus (T2DM) and non-diabetic controls in relation to measures of adiposity.

Methods

Levels of leptin and adiponectin were measured in 100 type 2 diabetics and 100 age-matched controls before and during falciparum malaria in a 2-year prospective study. Also, waist circumference (WC), weight, height and hip circumference were measured. Body mass index (BMI) and waist-to-hip ratio (WHR) were computed.

Results

At baseline, diabetics had significantly (p < 0.05) higher WC and BMI but lower WHR, leptin and adiponectin levels. Baseline leptin correlated positively with WC (r = 0.633; p < 0.001) and BMI (r = 0.63; p < 0.001) in diabetics but only BMI (0.562; p < 0.001) in non-diabetic controls. Baseline leptin and adiponectin correlated positively (r = 0.249; p = 0.029) in non-diabetic respondents only. Adiponectin correlated negatively with WC (r = −0.58; p = 0.006) in diabetic males only. During malaria, mean levels of leptin and adiponectin were comparable (p > 0.05) between diabetics and controls. However, compared to baseline levels, significant (p < 0.001) elevation of adiponectin was found in both study groups. In respect of leptin, significant (p < 0.001) rise but decline was observed in diabetics and controls respectively. Malaria-induced leptin correlated negatively with adiponectin (r = −0.694; p < 0.001) in non-diabetic controls only.

Conclusion

Diabetics and controls exhibited increased adiponectin levels due to falciparum malaria but differed in response in terms of leptin levels.

Relationships between serum omentin-1, body fat mass and bone mineral density in healthy Chinese male adults in Changsha area

PURPOSE

The present study is firstly designed to identify the relationship between serum omentin-1 concentration, body fat mass and bone mineral density in healthy Chinese male adults in Changsha city.

METHODS

A total of 219 (20-80 years old) healthy subjects were enrolled in this cross-sectional study. Serum omentin-1, adiponectin, leptin, resistin and bone turn over biochemical markers were measured with enzyme-linked immunosorbent assay. Bone mineral density (BMD) and fat body composition were determined using dual-energy-X-ray absorptiometry.

RESULTS

Serum omentin-1 levels in the overweight subjects were significantly lower than those of the subjects with normal weight (p < 0.05). Omentin-1 was negatively correlated with weight (r = -0.418), body mass index (BMI, r = -0.419), waist circumference (r = -0.402), waist-to-hip ratio (WHR, r = -0.355), fat body mass (FBM, r = -0.430), fat % (r = -0.408), trunk fat (-0.431). However, after controlling for age, BMI and FBM, no significant correlation was noticed between omentin-1 and BMD at different skeletal sites. Pearson's correlation coefficients and partial correlation coefficients after adjustment showed no significant correlations between omentin-1 and bone turn over biochemical markers, including bone-specific alkaline phosphatase and bone cross-linked N-terminal telopeptides of type I collagen. Multiple line stepwise regression analysis revealed that FBM, WHR, adiponectin were important variables affecting omentin-1. Moreover, lean tissue mass was the most important factor affecting BMD and explained 10.5-14.7 % of the variance. Omentin-1, leptin and resistin were not the predictors of BMD.

CONCLUSIONS

Serum omentin-1 was negatively correlated with FBM and BMI in healthy Chinese male adults, It was not significantly correlated with bone turnover biochemical markers. Omentin-1 may exert ambiguous effects on BMD, which maybe caused by the complex interactions among adipokines, hormonal activity, and body composition and bone metabolism.

Decreased circulating leptin level and its association with body and bone mass in girls with adolescent idiopathic scoliosis

STUDY DESIGN

A prospective study was designed to investigate the circulating leptin level in girls with adolescent idiopathic scoliosis (AIS).

OBJECTIVE

To determine the circulating leptin levels in AIS girls, and to investigate its associations with body mass and bone mass.

SUMMARY OF BACKGROUND DATA

Abnormal growth pattern and osteopenia have been well documented in AIS patients throughout the peripubertal growth period. Leptin has been shown to regulate the growth of the whole body and bone particularly during childhood and adolescence. However, the circulating level of leptin, the relationships between leptin and lower body mass, and the relationships between leptin and lower bone mass in AIS patients remain unclear.

METHODS

One hundred twenty AIS girls and 80 healthy controls were recruited in this study. Measurements of anthropometry and circulating leptin were performed both in AIS and non-AIS girls. Evaluations of curve severity and measurements of bone mineral content/density (BMC/BMD) were performed only in AIS girls. The anthropometric data and circulating leptin levels were compared between older AIS girls and controls. The relationships between leptin and age, menstrual status, body weight, height, body mass index (BMI), Risser sign, curve magnitude, and BMC/BMD were analyzed in AIS girls.

RESULTS

Compared with healthy controls, an abnormal growth pattern (higher corrected height, lower weight, and lower BMI), and a marked decrease of circulating leptin were found in AIS girls, even after the adjustment for age and menstrual status. Positive correlations were found between leptin and age, menstrual status, body weight, height, BMI, and Risser sign. No significant correlation was found between leptin and curve magnitude. There was no significant difference in age at menarche between menstruating AIS and non-AIS girls, though an inverse correlation was observed between leptin and the age at menarche. The relationship between leptin and BMC/BMD remained significantly positive after controlling for age and menstrual status, although it was not independent of body weight or BMI.

CONCLUSION

A marked decrease of circulating leptin was observed in the current study. There was an association between leptin and body weight, BMI, other growth parameters, and BMC/BMD. This correlation suggests that leptin might play an important role in the lower body and bone mass in AIS girls.