Serum insulin-like growth factor I in a random population sample of men and women: relation to age, sex, smoking habits, coffee consumption and physical activity, blood pressure and concentrations of plasma lipids, fibrinogen, parathyroid hormone and osteocalcin.

Abstract

There is a clinical need for population based reference values for serum insulin-like growth factor I (IGF-I). We have therefore determined serum IGF-I concentrations in a random population sample from Sweden and have related the levels to age, sex, life style factors, blood pressure, body composition, blood lipids, plasma fibrinogen, parathyroid hormone (PTH) and osteocalcin. Within the framework of the WHO MONICA Project in the city of Göteborg, Sweden, 197 men and 195 women aged 25-64 years were studied. Women aged 25-34 years had higher IGF-I concentration than men (mean 278 vs 227 micrograms/l) but in the interval 55-64 years values were lower in women than in men (158 vs 171 micrograms/l). IGF-I correlated positively with height and inversely with age, body mass index, systolic blood pressure and total cholesterol in both sexes. Negative relations between IGF-I and high density lipoprotein-cholesterol, as well as with amount of tobacco smoked, were found in men, and between IGF-I and diastolic blood pressure, triglycerides and PTH in women. When age was allowed for in multivariate analyses, most of these relations disappeared. However, among men IGF-I was positively associated with fibrinogen and negatively with age and smoking. IGF-I was negatively associated with age and coffee consumption in women. The present data can be used as reference values for IGF-I (at least in Caucasians) for the diagnosis of growth hormone disturbances and as guidelines for growth hormone substitution.