Children with overweight or obese body mass index measures at preschool age were significantly more likely than were normal weight children to suffer upper- and lower-limb fractures before age 15 years, according to data from almost 470,000 children.
Previous studies of adults have shown associations between obesity and fractures, but the impact of higher BMI at preschool age on fracture incidence later in childhood has not been explored, according to Jennifer C.E. Lane, MD, of the University of Oxford (England), and colleagues. “A focused study of the association between preschool obesity and fracture risk offers the opportunity to better understand the impact of obesity in early life,” they wrote in the Journal of Bone and Mineral Research.
The researchers reviewed data from 466,997 children at 296 primary care centers using the Information System for Research in Primary Care, a Spanish national database, for the years 2003-2013. The children were assessed starting at age 4 years and followed until age 15 years or until they left the region or died, or until the study period ended, on Dec. 31, 2016. The average follow-up time was 4.9 years, and 49% of the children were girls. BMI categories were determined via the World Health Organization growth standards for calculating age- and sex-specific BMI z scores, and the categories were defined as underweight (< −2 BMI z score), normal weight (−2 to +2 BMI z score), overweight (> +2 BMI z score), and obese (> +3 BMI z score).
Overall, children with a BMI in the overweight or obese ranges at first assessment were significantly more likely than were their normal weight counterparts to suffer lower-limb fractures (adjusted hazard ratios, 1.42 and 1.74, respectively) and upper-limb fractures (aHRs, 1.10 and 1.19, respectively) during the follow-up period.
The total incidence of fractures during childhood for those in the study who were underweight, normal weight, overweight, or obese, was 9.20%, 10.06%, 11.28%, and 13.05% respectively.
In a secondary analysis, fracture risk varied by anatomic location and reflected previous findings showing an increased risk of distal limb fractures associated with high BMI, the researchers said.
The findings were limited by several factors, including the smaller-than-average proportion of children with overweight or obese BMI measures, the imprecise nature of the BMI z score as a predictor of obesity in children, and the lack of data on sports, medical issues, and general activity levels, the researchers noted.
However, the results were strengthened by the population-based sample and long-term follow-up, and the work “suggests that interventions to treat obesity in early childhood could have benefits for the primary or secondary prevention of fractures later in childhood, especially in the prevention of fractures within the forearm and hand or foot and ankle,” the authors concluded.
The study was supported in part by the NIHR Biomedical Research Centre, Oxford, and La Marató de TV3 Foundation. Dr. Lane disclosed funding from a Versus Arthritis Clinical Research Fellowship but had no financial conflicts to disclose. Some authors reported relationships with numerous pharmaceutical firms.
SOURCE: Lane JCE et al. J Bone Miner Res. 2020 Apr 7. doi: 10.1002/jbmr.3984