Relationship between ghrelin and the metabolic syndrome in the elderly: a longitudinal population-based study

Ghrelin regulates energy homeostasis and may contribute to the development of the metabolic syndrome (MS) in the elderly. To study the relationship between ghrelin and the MS, IGF-I and life style factors over a 2-year follow-up. Longitudinal population-based study, starting from 2002; 2 years follow-up. Three hundred and thirteen (153 men/160 women) individuals living independently older than 70 years. MS was found in 54.9% of men and 61% of women. In the 229 subjects available at follow-up, ghrelin was higher in men than in women at basal (P = 0.002) and 2-year follow-up (P = 0.004). Ghrelin decreased over time in both genders (P < 0.01). Ghrelin was lower in individuals showing MS compared to non-MS (P = 0.08), but this difference was more evident at 2-year follow-up (P = 0.016), mostly due to men with MS (P = 0.002) and even after adjustment for BMI, gender and age. Individuals with MS had an OR of 1.67 (95% CI: 1.0-2.78) for low ghrelin (< first tertile); when adjusting by BMI, gender and age, only high triglycerides with OR 1.8 (1.0-3.3), remained statistically significant among the MS components. IGF-I showed a positive correlation with ghrelin only in individuals without MS (r(s) 0.403, P < 0.001) with no gender differences; this relationship was not found in MS (r(s) 0.120, P = 0.129). A positive association of ghrelin was found with academic level, alcohol consumption and smoking. Ghrelin is higher in old men in comparison to women and decreases over time with a steeper decline in subjects with MS; moreover, in these subjects ghrelin/IGF-I correlation is lost.