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Age-related decrease in IGFs may affect fat mass regulation
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Concentrations of insulin-like growth factors I and II appear to diminish with age, with greater reductions associated with higher levels of fat mass, according to research published in Obesity.
The findings, based on data from a longitudinal British birth cohort study, could offer evidence for the roles of IGF-I and IGF-II in regulating fat mass, but not lean mass, in late midlife.
“Findings from the present study add substantially to our understanding of the age-related changes in IGF-I and II, and their consequences for body composition,” the researchers wrote.
“However, the implications of these findings are not straightforward.”
David Bann, PhD, of the University College London, and colleagues studied data from 1,542 men and women from the Medical Research Council National Survey of Health and Development, a socially stratified sample of births with follow-up across life.
The researchers measured participants’ blood samples at age 53 years and/or from age 60 to 64 years using immunoassay. Fat mass, android to gynoid fat ratio and appendicular lean mass also were assessed from age 60 to 64 years through DXA. The investigators used conditional change linear regression models to examine the relationships between changes in IGF-I or IGF-II and body composition outcomes.
Participants demonstrated lower mean IGF-I and IGF-II concentrations from age 60 to 64 years compared with age 53 years, with a 12.8% difference for IGF-I and 12.5% difference for IGF-II. Greater reductions in IGF-I or IGF-II were linked to higher fat mass from age 60 to 64 years.
Higher IGF-I at age 53 years was associated with elevated lean mass; however, there was little evidence connecting changes in IGF-I or IGF-II to lean mass.
Although pharmacologic IGF supplementation to lower fat mass levels would be unlikely considering probable increases in cancer risk, the researchers highlighted opportunities for earlier action.
“Behavioral or early life interventions acting on the upstream determinants of IGF-I and II may potentially lessen their decline with age in later midlife, and in turn could limit the accumulation of fat mass during this period of ageing,” the researchers wrote. – by Allegra Tiver
Disclosure: The researchers report no relevant financial disclosures.
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