Article

Relationship between serum leptin levels and bone mineral density and bone metabolic markers in patients on hemodialysis.

Research Development Center, Imam Khomeini Hospital Complex, Tehran University of Medical Science, Tehran, Iran.
Saudi journal of kidney diseases and transplantation: an official publication of the Saudi Center for Organ Transplantation, Saudi Arabia 01/2013; 24(1):41-7. DOI: 10.4103/1319-2442.106238
Source: PubMed

ABSTRACT Leptin is the protein product of the obesity gene, which is produced in fat tissue. It was originally thought to be involved only in the regulation of food intake and energy balance. We aimed to investigate the relationship of serum leptin levels with bone mineral density (BMD) and biochemical markers of bone turnover in patients on hemodialysis (HD). This study included 72 patients (43 males and 29 females), whose mean age was 55.1 ± 11.4 years, mean body mass index was 23.13 ± 2.75 kg/m 2 and mean duration on HD was 5 ± 3.4 years. The BMD values were calculated using dual-energy X-ray absorptiometry (DEXA) at the femoral neck and lumbar spine. Blood samples were taken for leptin, intact parathyroid hormone (I-PTH), bone alkaline phosphatase (BAP), calcium (Ca), phosphate (P) and albumin. The leptin levels were higher in females than in males (22.3 ± 19.6 vs 20.8 ± 23), but this difference was not significant. The serum leptin level had a strong positive correlation with Ca levels in the female patients (r = 0.659 and P = 0.01) and a negative correlation with albumin levels (r = -0.461 and P = 0.01). No correlation was found with age, BMI, duration on dialysis, BMD and serum levels of PTH, BAP and P for the entire patient group or either gender separately. The serum leptin level was significantly lower in females with PTH >300 pg/mL when compared with patients with PTH = 100-300 pg/mL (86 ± 85 vs 47 ± 48) (P = 0.011).Women with BAP <300 IU/L had significantly higher serum leptin than those with BAP 300-600 IU/L (P = 0.024). Women with Ca <8.5 mg/dL had significantly lower serum leptin levels compared with those with Ca levels of 8.5-10.5 mg/dL (P = 0.011). There was no significant difference between the two genders among variables such as age, BMI, duration on dialysis, serum leptin, I-PTH, Ca, P, BAP, albumin and BMD of the femoral neck and lumbar spine.

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