To assess the association of subclinical thyroid dysfunction with fractures.

Medline, Embase, Pubmed, Cochrane Library, CBM, CNKI, Wan Fang, and VIP databases were systematically searched from January 1990 to August 2015 to identify prospective cohort studies which have studied the risk of fracture in patients with subclinical thyroid dysfunction. The relative risks(RR)of cohort studies were pooled respectively, depending on the result of heterogeneity test among the individual studies search. The Stata(version 13.0)software was used for meta-analysis.

Nine prospective cohort studies including 292 460 participants were identified as eligible for the meta-analysis. RR of subclinical hyperthyroidism for fracture was 1.39(95%CI 1.24-1.55); for hip fracture, RR was 1.24(95%CI 1.10-1.40); for nonspine fracture, RR was 1.32(95%CI 1.09-1.60). Different gender for subclinical hyperthyroid was associated with higher fracture rates: for females, RR was 1.15(95%CI 1.04-1.27); for males, RR was 1.31(95%CI 1.08-1.59). The incidence of fracture in patients with subclinical hyperthyroidism was higher during the follow-up. For subclinical hypothyroidism, the RR was 1.21(95%CI 1.03-1.42). Subgroup analysis indicated that there were significant differences between endogenous/exogenous subclinical hyperthyroidism and euthyroid, but no differences between endogenous/exogenous subclinical hypothyroidism and euthyroid were found.

Subclinical hyperthyroidism is associated with an increased risk of fracture in the population, especially hip fracture and nonspine fracture. During the course of subclinical hyperthyroidism, the incidences of fracture should be noticed both in females and males. However, there is no evidence which could prove a definite association between subclinical hypothyroidism and the risk of fracture. (Chin J Endocrinol Metab, 2017, 33: 103-110)

Subclinical hyperthyroidism; Subclinical hypothyroidism; Fractures