Childhood BMI linked to future hip fracture risk
MedWire News: Women who were thin in childhood may have an increased risk for hip fracture, indicates research published in the journal Osteoporosis International.
Study author Cyrus Cooper (Southampton General Hospital, UK) and colleagues suggest their findings “could be a direct effect of low fat mass on bone mineralization, or represent the influence of altered timing of pubertal maturation.”
Using a national register the team examined the incidence of hip fracture among 6370 women born in Helsinki, Finland, between 1934 and 1944. The women’s weight and height at birth and through childhood were also collated.
Overall, 49 of the women experienced hip fracture over 187,238 person-years of follow-up.
Birth weight and height did not significantly differ between women with and without hip fracture, and body mass index (BMI) at 1 year was slightly higher in women who had sustained hip fracture than those who had not. However, by the age of 12 years BMI was significantly lower in hip fracture patients than controls.
Analysis revealed a correlation with hip fracture when the increasing Z-scores for height were not matched by the increase in height between age 1 and 12 years.
There was a significant relationship between reduction in Z-score for body mass index (BMI) and increased risk for hip fracture, with women in the lowest quarter of change in Z-score for BMI at 12 years a significant 8.2 times more likely to experience hip fracture than those in the highest quarter.
“Our data suggest that it is the rate of change in BMI, rather than the absolute BMI at any age during childhood that is the key determinant of later hip fracture,” Cooper et al observe.
“Reduction in Z-scores for BMI may reflect a relative loss of fat mass, but could also reflect a relative reduction in muscle mass,” they note. MedWire News/ Amgen – bone health
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By Lynda Williams