Serum IGF1, metabolic syndrome, and incident cardiovascular disease in older people: a population-based study
Christa C van Bunderen1, Mirjam M Oosterwerff, Natasja M van Schoor
1Departments of Internal Medicine, section Endocrinology ZH 4A62, Amsterdam, The Netherlands. c.vanbunderen@vumc.nl
Insights
High insulin-like growth factor 1 (IGF1) levels are linked to metabolic syndrome in older adults. Both low and high IGF1 levels, with or without metabolic syndrome, increase cardiovascular disease (CVD) risk.
Area of Science:
- Endocrinology
- Cardiovascular Medicine
- Gerontology
Background:
- Contradictory associations exist between insulin-like growth factor 1 (IGF1) levels and cardiovascular diseases (CVD).
- Understanding the role of metabolic syndrome in the IGF1-CVD relationship may clarify these discrepancies.
Purpose of the Study:
- To investigate the association between IGF1 concentration and prevalent metabolic syndrome.
- To examine whether metabolic syndrome mediates the relationship between IGF1 and incident CVD over 11 years.
Main Methods:
- Utilized data from the Longitudinal Aging Study Amsterdam (n=1258, age ≥65).
- Metabolic syndrome diagnosed per NCEP ATP III criteria.
- CVD ascertained via self-reports and mortality data.
Main Results:
- Higher IGF1 levels (fourth quintile) associated with prevalent metabolic syndrome (OR 1.59).
- High-normal IGF1 linked to high triglycerides in women.
- Metabolic syndrome did not mediate the U-shaped IGF1-CVD association.
- Both low IGF1 (without metabolic syndrome) and high IGF1 (with metabolic syndrome) increased CVD risk.
Conclusions:
- High-normal IGF1 levels correlate with metabolic syndrome and high triglycerides in older adults.
- Suggests distinct pathophysiological pathways for low and high IGF1 levels in relation to incident CVD.
Objective:
High as well as low levels of IGF1 have been associated with cardiovascular diseases (CVD). The relationship of IGF1 with (components of) the metabolic syndrome could help to clarify this controversy. The aims of this study were: i) to investigate the association of IGF1 concentration with prevalent (components of) the metabolic syndrome; and ii) to examine the role of (components of) the metabolic syndrome in the relationship between IGF1 and incident CVD during 11 years of follow-up.
Methods:
Data were used from the Longitudinal Aging Study Amsterdam, a cohort study in a representative sample of the Dutch older population (≥65 years). Data were available in 1258 subjects. Metabolic syndrome was determined using the definition of the US National Cholesterol Education Program Adult Treatment Panel III. CVD were ascertained by self-reports and mortality data.
Results:
Levels of IGF1 in the fourth quintile were associated with prevalent metabolic syndrome compared with the lowest quintile (odds ratio: 1.59, 95% confidence interval (CI) 1.09-2.33). The middle up to the highest quintile of IGF1 was positively associated with high triglycerides in women. Metabolic syndrome was not a mediator in the U-shaped relationship of IGF1 with CVD. Both subjects without the metabolic syndrome and low IGF1 levels (hazard ratio (HR) 1.75, 95% CI 1.12-2.71) and subjects with the metabolic syndrome and high IGF1 levels (HR 2.28, 95% CI 1.21-4.28) demonstrated increased risks of CVD.
Conclusions:
In older people, high-normal IGF1 levels are associated with prevalent metabolic syndrome and high triglycerides. Furthermore, this study suggests the presence of different pathomechanisms for both low and high IGF1 levels and incident CVD.
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