The association of schooling, sibling life situation, and dietary habits with the estimated 24-h urinary salt excretion and sodium-to-potassium ratio in 3-year-old children

We examined the association of schooling, sibling life situation, and dietary habits with the estimated 24-h urinary salt excretion and the urinary sodium-to-potassium (Na/K) ratio in 3-year-old children. The subjects were 639 children who underwent a health checkup in four cities and towns in Kyoto Prefecture from January to November 2019. The children’s parents answered questionnaires about weekday childcare places, the birth order, and the awareness of reducing the salt intake. The questions on food intake frequency included 10 items. The estimated 24-h salt excretion and Na/K ratio were calculated from the participants’ first voiding urine in the morning. Data were available for 294 children. The median (interquartile range (IQR)) of salt excretion (g/day) was 2.6 (1.7–3.4), and urinary Na/K ratio (mmol ratio) was 2.6 (1.6–4.1). Multinomial logistic regression analysis showed that the group with older siblings was significantly associated with high salt (odds ratio 1.89 (95% confidence interval 1.04 to 3.46)). In the urinary Na/K ratio, the nursery group had a significantly lower Na/K (odds ratio 0.32 (0.17 to 0.60)). High processed meat products intake was associated with a higher Na/K (odds ratio 1.96 (1.05–3.66)), whereas high vegetable intake was associated with a lower Na/K (odds ratio 0.45 (0.23–0.87)). Other factors showed no significant associations. In Japanese 3-year-old children, the estimated 24-h urinary salt excretion was associated with older siblings, and the urinary Na/K ratios were associated with schooling situation and the intake of processed meat products and vegetables.本研究旨在探究3岁儿童的托育就学情况、同胞状况与膳食习惯，与其估算的24小时尿盐排泄量及尿钠钾（Na/K）比值之间的关联。研究对象为2019年1月至11月期间，在日本京都府4个市镇接受健康检查的639名儿童。儿童家长填写了涵盖工作日托育场所、出生顺序及减盐认知的调查问卷，其中食物摄入频率相关问题共设10项。研究人员通过受试者的晨起首次排尿样本，计算得到其估算的24小时尿盐排泄量与尿钠钾比值。最终纳入有效分析数据的儿童共294名。尿盐排泄量（单位：克/天）的中位数（四分位距（interquartile range, IQR））为2.6（1.7~3.4）；尿钠钾比值的中位数（四分位距（interquartile range, IQR））为2.6（1.6~4.1），单位为毫摩尔比值。多项逻辑回归（multinomial logistic regression）分析结果显示，拥有年长同胞的儿童群体，其尿盐排泄量显著更高（优势比（odds ratio, OR）=1.89，95%置信区间（confidence interval, CI）：1.04~3.46）。针对尿钠钾比值的分析显示，接受托育机构照护的儿童组，其尿钠钾比值显著更低（OR=0.32，95%CI：0.17~0.60）。较高的加工肉制品摄入与更高的尿钠钾比值相关（OR=1.96，95%CI：1.05~3.66）；而较高的蔬菜摄入则与更低的尿钠钾比值相关（OR=0.45，95%CI：0.23~0.87）。其余因素未观察到显著关联。综上，在日本3岁儿童群体中，估算的24小时尿盐排泄量与是否拥有年长同胞存在关联，而尿钠钾比值则与托育就学状况、加工肉制品及蔬菜摄入情况相关。