Abstract
BACKGROUND: Zinc is an essential micronutrient involved in metabolic pathways, yet its association with the development of abdominal obesity (AO) is not well established. This study examined the relationship between serum zinc (SZn) concentrations and the incidence of AO, considering potential sex-specific differences. METHODS: We included 1533 adult participants of the fourth phase (2009-2011) of the Tehran Lipid and Glucose Study (mean age of 43.6 ± 13.9 years, 34.3% male) and followed them up to 2018-2022. SZn concentration was measured at baseline by the flame atomic absorption spectrometry. Anthropometric measurements were done at baseline and again at three-year intervals to determine AO incidence. Univariate unrestricted regression spline (UVRS) and sex-stratified Cox proportional hazard models were used. RESULTS: The mean (SD) of WC was 85.0 ± 6.4 cm, and the mean SZn concentration was 113 ± 46.0 µg/dL at baseline. After a median of 9.3 years follow-up, 30.1% of participants (27% of male and 31.7% of female) developed AO. A non-linear association was observed between SZn and the incidence of AO (non-linearity from the likelihood ratio test P < 0.05). SZn concentrations above 127.5 µg/dL were associated with a reduced risk of AO by 34% in female (HR = 0.66, 95% CIs = 0.47-0.91). No significant association was found in male between SZn and the risk of developing AO over time. CONCLUSION: Our study demonstrated that a higher SZn concentration was negatively associated with the risk of developing AO in female. This finding may imply that a higher intake of zinc-rich food sources may protect against developing AO in female.