NEW YORK (Reuters Health)—A Dutch study confirms that reduced serum levels of insulin-like growth factor-1 (IGF-1) are associated with increased fracture risk in elderly women, but not men.
In an Aug. 31 online paper in the Journal of Clinical Endocrinology & Metabolism, Dr. N.C. van Varsseveld, of VU University Medical Center, Amsterdam, and colleagues noted that some previous study results have been conflicting, with a number mixing young and old and others restricted to men or women.
In the current study, the team examined data on 627 men and 656 women aged at least 65 years participating in an ongoing, population-based cohort study. They were examined at baseline and after three years. Fracture incidence was prospectively charted over 10 years.
At three years, women but not men in the lowest quintile of IGF-1 concentration had lower broadband ultrasound attenuation and a greater three-year decrease in total hip bone mineral density than those in the highest quintiles.
Compared to women in the highest quintile of IGF-1, women in the combined lowest four quintiles of IGF-1 had an almost doubled 10-year fracture risk (hazard ratio 1.98; p=0.05).
Exclusion of respondents using estrogens or bisphosphonates from the fully adjusted models did not materially change the results.
Potential mechanisms underlying these findings, the investigators wrote, “are complex and largely unclear.” However, they add, “This marked gender difference is in accordance with findings in other population based studies including both men and women.”
The investigators concluded that “more studies on the association between IGF-1 and bone in older persons are recommended in order to elucidate complex underlying mechanisms.”
Commenting on the findings by email in a joint statement, Drs. Kerstin Landin-Wilhelmsen, of the University of Gothenburg, Sweden, and Emily Krantz of Sodra Alvsborgs Hospital, Boras, Sweden, who have conducted research in the field, told Reuters Health, “The study showed fairly weak correlations between the lowest quartile in serum IGF-1 in women and fracture prevalence three years later. It is known that serum IGF-1 is dependent on age, sex, body weight, height, nutritional, medical and health status.”
“Hence,” they concluded, “the comparison between men and women is questionable as the body composition and hormonal profile are so different.”
Dr. van Varsseveld did not respond to requests for comments.
The Longitudinal Aging Study Amsterdam is supported by the Netherlands Ministry of Health Welfare and Sports and the Directorate of Nursing Care and Older Persons. The authors reported no disclosures.