Plasma insulin-like growth factor I levels in the elderly: Relation to plasma dehydroepiandrosterone sulfate levels, nutritional status, health and mortality

Background: Insulin-like growth factor I (IGF-I) has beneficial metabolic e ffects. Because plasma IGF-I levels have been reported to be enhanced by de hydroepiandrosterone (DHEA) administration, it has been suggested that the IGF-I may be implicated in some of the reported associations between low DH EA sulfate (DHEAS) levels and impaired health measures in elderly subjects. The nutritional status, which also regulates plasma IGF-I levels, is also an important determinant of health outcome. Objective:We sought to investig ate the associations between plasma IGF-I revels and plasma DHEAS levels, n utritional status, health, and mortality in the elderly. Methods: In 256 co mmunity-dwelling subjects aged 65-101 years, enrolled in the Paquid study, a health questionnaire was used to a certain their functional disabilities, any history of medical disorders, self-perceived health, depressive sympto ms, and their cognitive function. Biological measurements included levels o f plasma IGF-I, albumin, transthyretin, and DHEAS. Mortality data were avai lable for 6 years following blood sampling. Results: In this elderly popula tion with no impairment in nutritional status, the plasma IGF-I levels decr eased significantly with age (p = 0.02). The plasma IGF-I levels correlated positively with those of transthyretin (p = 0.0001). IGF-I also correlated with DHEAS (p = 0.04), but the correlation did not remain significant afte r adjustment for age. As opposed to SDHEA, the plasma IGF-I revels did not correlate with the results from the hearth questionnaire. The baseline IGF- I values in the highest tertile were associated with a higher risk of short -term mortality than those in the lowest tertile (RR = 8.4 at 2 years, p = 0.007). Conclusions: Our results suggest that IGF-I is not connected with t he association between low plasma DHEAS levels and the impaired results fro m the health questionnaire. The relationship between plasma IGF-I highest l evels and mortality should be further explored. Copyright (C) 2001 S. Karge r AG, Basel.