Abstract 1676: Relationship Between Leptin and Albuminuria in African Americans: Jackson Heart Study
Leptin is an adipocyte derived hormone. Higher leptin levels have been shown to be associated with processes related to cardiovascular disease (CVD), such as leptin resistance, insulin resistance and changes in systemic inflammation. Similarly, albuminuria is a known independent risk factor for CVD and CVD mortality. However, it is unclear whether higher leptin levels are independently associated with albuminuria. We examined the hypothesis that higher serum leptin levels are positively associated with albuminuria. We analyzed data from the Jackson Heart Study, a population-based study of African Americans (aged > 21 years, 62% women) in three counties in Mississippi, who were free of CVD (n=2895). Serum leptin levels was examined as gender specific quartiles (quartiles 1– 4 in women: 0 –22.65 ng/mL, 22.66 –33.9 ng/mL, 34.0 – 47.1 ng/mL, > 47.1 ng/mL; quartiles 1– 4 in men: 0 – 4.8 ng/mL, 4.9 – 8.2 ng/mL, 8.3–14.0 ng/mL, >14.1 ng/mL). The main outcome of interest was albuminuria (n=346), defined as a urinary albumin: creatinine ratio of >30 mg/g based on spot urine and 24 hour samples. Overall, there was a clear positive association between increasing quartiles of serum leptin and albuminuria, independent of confounders such as age, gender, education, body mass index, smoking, alcohol intake, diabetes, hypertension, systolic and diastolic blood pressure, glycosolated hemoglobin and serum cholesterol levels. Compared to the lowest quartile of leptin (referent category), the multivariable odds ratio (95% confidence interval) of albuminuria for quartiles 2– 4 respectively was 1.45 (0.95, 2.22), 2.16 (1.39 3.37) and 2.49 (1.56, 3.98); p-trend<0.0001. This observed positive association persisted in separate analyses among women (p-trend<0.0001) and men (p-trend<0.0001), normal weight (p-trend<0.0001) and overweight/obese weight individuals (p-trend<0.0001), as well as among study subjects free of diabetes or hypertension (p-trend<0.0001), suggesting this association to be independent of these factors. In conclusion, higher serum leptin levels are positively associated with albuminuria. Our results suggest that at least part of the previously reported association between albuminuria and CVD may be mediated through leptin resistance.