Table 1. Participants’ demographic, anthropometric, and urinary parameters by children’s sex (mean ± SD or %).
| Variables | Subcategories | Total children (n = 329) |
Girls (n = 157) |
Boys (n = 172) |
pa value |
|---|---|---|---|---|---|
| Children | |||||
| Age (years) | 9.0 ± 1.2 | 9.0 ± 1.2 | 8.9 ± 1.2 | 0.664 | |
| Geographical area (%) | 0.656 | ||||
| <50000 inhabitants | 46.5 | 45.2 | 47.7 | ||
| >50000 inhabitants | 53.5 | 54.8 | 52.3 | ||
| Anthropometric data | |||||
| Weight (kg)† | 35.6 ± 8.5 | 35.8 ± 8.8 | 35.4 ± 8.1 | 0.654 | |
| Height (cm) | 137.3 ± 8.9 | 137.0 ± 9.5 | 137.6 ± 8.2 | 0.939 | |
| BMI (kg/m2)† | 18.7 ± 3.2 | 18.9 ± 3.2 | 18.6 ± 3.2 | 0.234 | |
| Urinary parameters | |||||
| Volume 24 h (mL/24 h)† | 907.2 ± 297.2 | 886.5 ± 284.9 | 926.1 ± 307.7 | 0.228 | |
| Creatinine/weight (mg/kg)† | 20.6 ± 4.3 | 19.4 ± 4.0 | 21.6 ± 4.4 | 0.000 | |
| UNa-24h (mEq/24 h) | 135.9 ± 51.9 | 127 ± 44.4 | 144.1 ± 56.8 | 0.007 | |
| UNa-24h (mg/24 h) | 3133 ± 1194 | 2921 ± 1022 | 3314 ± 1306 | 0.007 | |
| Salt (g/day) | 7.9 ± 3.0 | 7.4 ± 2.6 | 8.4 ± 3.3 | 0.007 | |
| Na/Creatinine (mg/mg) | 4.4 ± 1.4 | 4.4 ± 1.4 | 4.4 ± 1.5 | 0.785 | |
| Parents | |||||
| Age (years)† | 42.0 ± 5.2 | 42.7 ± 5.1 | 41.5 ± 5.3 | 0.008 | |
| Father's employment status (%) | 0.659 | ||||
| Non-paid work/no work | 11.9 | 12.7 | 11.0 | ||
| Private company | 65.3 | 62.4 | 68.0 | ||
| Official position | 16.1 | 17.8 | 14.5 | ||
| Retired | 1.2 | 0.6 | 1.7 | ||
| DK, NA | 5.5 | 6.4 | 4.7 | ||
| Mother's employment status (%) | 0.195 | ||||
| Non-paid work/no work | 36.8 | 32.5 | 40.7 | ||
| Private company | 45.0 | 48.4 | 41.9 | ||
| Official position | 16.4 | 18.5 | 14.5 | ||
| Retired | 0.9 | 0.0 | 1.7 | ||
| DK, NA | 0.9 | 0.6 | 1.2 | ||
† Data do not follow a normal distribution. BMI: Body Mass Index. DK, NA: do not know, no answer. UNa-24h: 24 h urinary sodium excretion.
a Significant difference according to sex group, as shown by the Student’s t-test for continuous and parametric variables, the Mann–Whitney U test for nonparametric variables (†), and the chi-square test among the groups. Significant differences are bolded.