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Serum Insulin-like Growth Factor-1 Level Associated with Bone Health and Fractures in Older Women

Osteoporosis-related fractures are associated with increased morbidity, mortality, and high economic costs. The pathogenesis of osteoporosis is multifactorial and GH-IGF-1 axis plays a role in this since it is a key factor in longitudinal bone growth, acquisition of bone mass and maintenance of adult bone mass. IGF-1 is present in both the systemic circulation and in the peripheral tissues, mediating GH to have direct effects on bones. Previous studies looking at the relationship between IGF-1 concentration and BMD had varying results.

Researchers write that the purpose of this study was “to investigate cross-sectional relationships between serum IGF-1 concentration and bone parameters, including quantitative ultrasound (QUS) and BMD, as well as longitudinal relationships between baseline serum IGF-1 concentration and three-year change in BMD and ten-year osteoporosis fracture risk in community-dwelling older men and women.”

Data in this study was collected in an ongoing multidisciplinary cohort study in community-dwelling elderly called the Longitudinal Aging Study Amsterdam (LASA). This was a random sample of men and women, aged 55-85 years, representative of the Dutch older population. The study included 627 men and 656 women.

Data were collected at baseline and every three years thereafter. IGF-1 concentrations were measured by an immunoradiometric assay after extraction. The reference range for both men and women for serum IGF-1 for age 60-70 years were 11-19 nmol/L. The reference range for > 70 years old was not defined, but was assumed to be towards the upper part of the reference range. IGF-1 concentrations was normally distributed over the study population.

QUS measurement of the heel used broadband ultrasound attenuation (BUA) and speed of sound. IGF-1 concentration were divided into 5 quadrants, with increasing in IGF-1 concentration. Results showed that women in the 1st quadrant of IGF-1 concentration (Q1; 7.3 nmol/L ± 1.7) had significantly lower BUA, a greater three-year decline in total hip BMD than women with the much higher IGF-1 concentration (Q5; 21.4 nmol/L ± 4.1). Moreover, women in Q1 of IGF-1 had an increased ten-year fracture risk than women in the higher quadrant of IGF-1 concentration. The authors suggest that lower IGF-1 level may lead to decreased bone formation and lower BMD, resulting in increased fracture risk. However, the true mechanism is unknown. Additionally, in men, no association was seen between IGF-1 concentration and BUA or BMD.

As these associations were not seen in men, the authors suggested that there is a gender difference over time. The data and analysis in this study may contribute to improvement of prevention and treatment strategies for osteoporosis, but more studies are warranted to understand the mechanism underlying the association.

Practice Pearls:

  • Lower IGF-1 concentration had lower BUA, greater three-year decline in total hip BMD, and increased in ten-year fracture risk.
  • Lower IGF-1 may reflect a poor general health status in older individuals.
  • No association between IGF-1 concentration and lower BUA or decline in BMD in men.

Van Varsseveld NC, Sohl E, Drent ML, and Lips P. “Gender-specific associations of serum insulin-like growth factor-1 with bone health and fractures in older persons.” Journal of Clinical Endocrinology & Metabolism, 26 Aug 2015. Web. 7 Sep 2015.