Leptin and Aging: Correlation with Endocrine Changes in Male and Female Healthy Adult Populations of Different Body Weights

Abstract

Aging is associated with changes in plasma levels of several hormones. There are conflicting reports on whether circulating leptin levels change during aging, the possible explanation for which is that alterations in adiposity and body mass index (BMI) also occur. In this study we measured plasma leptin and other hormonal parameters known to influence leptin in 150 men and 320 women of a wide age (18-77 yr) and BMI (18.5-61.1 kg/m2) range. Subjects of each gender were separated into 2 groups of similar BMI, i.e. nonobese (BMI, <30) and obese (BMI, >30), and treated separately. Statistical analysis was performed, treating each group of subjects as a whole population or divided into age groups (<30, 30-50, and >50 yr). BMI-adjusted leptin levels were progressively lower with increasing age in women, with a consistent fall after menopause (-21%; P < 0.001); in men, leptin levels also tended to be lower in subjects more than 50 yr of age, but the reduction was not significant. Multiple linear regression analysis, performed on subjects treated either as a whole population or divided into obese and nonobese, showed that in both genders BMI and age were independent contributors of leptin levels, and there was an inverse relationship between leptin and age in both obese (standardized coefficient beta = -0.25 in women and -0.23 in men; P < 0.01) and nonobese (-0.22 in women and -0.20 in men; P < 0.05) subjects. The correlation of leptin and age with plasma levels of sex and thyroid hormones, GH, insulin-like growth factor I, PRL, and insulin was also evaluated. The variables that correlated with leptin were included in a multiple regression model that included BMI and age. Testosterone in men (-0.43 in nonobese and -0.19 in obese; P < 0.05) and estradiol in women (0.22 in nonobese and 0.24 in obese; P < 0.05) were important contributors to leptin levels; also, dehydroepiandrosterone sulfate in obese women (-0.16) and sex hormone-binding globulin in obese subjects of both genders (0.15 in women and 0.19 in men) were significant determinants in the model. However, none of the hormonal parameters abolished the negative correlation between leptin and age or the gender difference in leptin levels. In conclusion, our data show that in adult humans of different body weight, serum leptin gradually declines during aging; leptin reduction is higher in women than in men, but it is independent from BMI and other age-related endocrine changes.

Leptin Levels in Children and Adults with Classic Galactosaemia

“…These differences and age-dependence of leptin concentrations become especially evident after appropriate logarithmic transformation (Blum et al 1997). Essentially, there is a significant correlation of leptin, or log-transformed values of leptin, and BMI in healthy males and females of a wide age range (5-77 years) (Isidori et al 2000;Gómez et al 2003;Falorni et al 1997). Contrary to what is expected, there was a lack of a correlation between log-leptin and BMI in adult males with Gal and in our entire adult Gal cohort.…”

Hip circumference is associated with the risk of premenopausal ER−/PR− breast cancer

“…43 Finally the rapid decline in circulating leptin levels rapidly decline after menopause. 44 This may contribute to the restriction to premenopausal women of the association between HC and ERÀ/PRÀ cancer risk.…”

Serum leptin level and cognition in the elderly: Findings from the Health ABC Study

“…Aging is associated with declining serum leptin levels, independent of body mass index (BMI), as well as with the development of leptin resistance (Isidori et al, 2000;Ma et al, 2002;Nogalska et al, 2003;Scarpace et al, 2001;Wang et al, 2001). In case-controlled studies, patients with AD have lower leptin levels than controls, also independent of body mass index (Power et al, 2001).…”