Figure 2.

Restricted cubic spline plots with their 95% confidence bands using linear mixed-effect model demonstrating sex-stratified association between the concentration and 24-hour excretion of urinary electrolytes (sodium, potassium, chloride, calcium, and magnesium) and 24-hour excretion of urine total protein and volume with average ambient temperature, adjusted for age, body mass index, physical exercise, smoking, alcohol consumption, sleep duration, religion, household wealth, time of visit, drinking water salinity, and humidity.