G(-2548)A leptin gene polymorphism in obese subjects is associated with serum leptin concentration and bone mass.
BACKGROUND
Clinical studies have shown either positive or in some other cases negative correlations between leptinemia and bone mineral density (BMD) or bone mineral content (BMC).


OBJECTIVE
The aim of the present study was to assess whether these discrepancies might be associated with the effect of G(-2548)A leptin or A326G and A668G leptin receptor gene polymorphisms on serum leptin concentrations or BMD and BMC.


METHODS
The study included 72 obese patients (39 women and 33 men, aged 46 +/-8.8 years; body mass index [BMI] >30 kg/m2). In all subjects, serum creatinine, glucose, lipids, leptin, and insulin were determined. Total fat mass (TFM), BMC, and BMD were assessed using dual energy X-ray absorptiometry (Lunar DPX-L).


RESULTS
No significant correlations were observed between body mass composition parameters (TFM, lean mass, BMC) or BMD in relation to genotypes. A positive correlation was found between serum leptin concentration and BMI. An inverse association was observed between leptin concentrations and BMC. Multiple regression analysis showed independent correlations of leptinemia with sex (P <0.001), TFM (P <0.000 001), BMC (P = 0.0001), and the presence of (-2548)A allele of the leptin gene (P <0.05). These parameters together accounted for 83% of variability in serum leptin concentrations.


CONCLUSIONS
In obese patients, serum leptin concentration shows an independent inverse correlation with BMD and male sex, but positively with TFM and the presence of -2548A allele of leptin gene. These parameters are responsible for 83% of leptin concentration variability. No correlations between the examined polymorphisms and BMC or BMD were found.
Franek
Edward
E
Department of Internal Diseases, Endocrinology and Diabetology, Central Clinical Hospital, Ministry for Internal Affairs, Warsaw, Poland. edward.franek@cskmswia.pl
Nowak
Jacek
J
Safranow
Krzysztof
K
Adler
Grazyna
G
Bińczak-Kuleta
Agnieszka
A
Ciechanowicz
Andrzej
A
Wiecek
Andrzej
A
D000328:Adult; D015992:Body Mass Index; D015519:Bone Density; D005260:Female; D006801:Humans; D020738:Leptin / Q000097:blood* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000235:genetics*; D011110:Polymorphism, Genetic
D020738:Leptin