Correlation between dietary selenium intake and stroke in the National Health and Nutrition Examination Survey 2003–2018

BACKGROUND: Epidemiologic evidence of the effect of dietary selenium intake on stroke risk remains controversial. This study aimed to examine the cross-sectional correlation between dietary selenium intake and the risk of stroke in adults. MATERIALS AND METHODS: We retrospectively analysed 39,438 participants from the National Health and Nutrition Examination Survey 2003–2018, aged 20–85 years. Participants were divided into quartiles depending on daily dietary selenium intake: quartile 1 (0–77 μg), quartile 2 (77–108 μg), quartile 3 (108–148 μg), and quartile 4 (148–400 μg). The dose-response relationship was assessed using the restricted cubic spline function. RESULTS: The adjusted odds ratios (ORs) and 95% confidence intervals (CIs) of stroke were 0.70 (0.55, 0.88) for participants in quartile 2, 0.71 (0.53, 0.93) for quartile 3, and 0.61 (0.43, 0.85) for quartile 4 compared with that in quartile 1. p-Value for trend through quartiles was .007. A non-linear negative correlation between dietary selenium intake and stroke was observed in the threshold effect analysis and restricted cubic spline function (p-value for non-linearity < .001). An initial decrease in odds of stroke lower than 105 μg/day selenium intake (0.61 [0.44, 0.85], p = .004) was followed by a platform beyond 105 μg/day (0.97 [0.81, 1.16], p = .723). In the subgroup analysis, adjusted ORs (95% CIs) of stroke were 0.51 (0.36, 0.70) for female participants, 0.63 (0.40, 0.99) for participants with age <60 years, 0.63 (0.47, 0.85) for participants with poverty-income ratio < 2.14, 0.66 (0.50, 0.87) for participants with overweight and obesity, 0.66 (0.52, 0.84) for participants with hypertension, 0.72 (0.53, 0.97) for participants without diabetes, and 0.72 (0.56, 0.92) for non-anaemic participants. CONCLUSIONS: Dietary selenium had a negative and non-linear correlation with the risk of stroke in adults. The correlation varied across different population subgroups. KEY MESSAGES: Dietary selenium had a negative and non-linear correlation with the risk of stroke in adults. Non-linear negative correlation trends were observed in subpopulations of females, age <60 years, poverty-income ratio <2.14, overweight and obesity, hypertension, non-diabetes, and non-anaemia. Dietary selenium intake of approximately 105 μg per day has an optimum effect on stroke.