Aging
Iodine Status and Bone Fracture Prevalence among Adults in the United States Alexander Hill* Alexander R Hill Hill Hill Hill University of Florida
Background: Excess or insufficient iodine intake can affect thyroid function and abnormal thyroid function can impact bone health and increase fracture risk. However, there are few studies on iodine status and bone health outcomes in older adults. To our knowledge, this study is the first to examine whether deficient or excess iodine status is associated with increased fracture prevalence among adults in the United States.
Methods: The study included 1,202 adults aged 50 years and over from the National Health and Nutrition Examination Survey (NHANES 2017 – 2020). We determined iodine status via urinary iodine concentrations adjusted for creatinine (UICadj). We defined iodine status as iodine-deficient (UICadj < 100 µg/L), excess (UICadj ≥ 300 µg/L), or normal (UICadj = 100-299 µg/L). We conducted survey-weighted, covariate-adjusted logistic regression models to examine associations between iodine status and prevalence of hip, spine, or wrist fracture for all participants and stratified by sex.
Results: Participants were 64 years old on average. Approximately, 28% of participants were iodine deficient, while 23% had excess UICadj levels. Approximately 19% of participants reported having had a bone fracture, with 13%, 5% and 3% reporting prior wrist, spine or hip fracture, respectively. Men with excess UICadj had higher odds of having had a hip fracture (OR: 3.70; 95%CI: 1.33 – 10.33; p = 0.01) compared to those with normal UICadj. There were also trends of associations of excess UICadj with higher odds of hip fracture in the overall sample of men and women (OR: 2.33; 95%CI: 0.92 – 5.93; p = 0.11), and spine fracture in men (OR: 3.41; 95%CI: 0.72 – 16.16; p = 0.13) compared to those with normal UICadj.
Conclusions: Excess iodine intake may be an underrecognized risk factor for bone fracture among men. Longitudinal studies are needed to examine associations between iodine status and bone health, as well as mediation by thyroid function, and sex-specific effects.