Table 1: General characteristics of families and respective infants in the study.

Mean (SD) 𝑃
CommunitiesItapuãBom FuturoPorto Velho

Family
 Fish meal, weeka2.63 (2.70)2.4 (1.4)1.97 (2.8)<0.000
 Family income US$227.93 (193.9)225.2 (146.1)247.30 (301.8)0.4771
 Maternal education, y6.56 (3.49)6 (2.7)8.7 (3.5)<0.000

Children
𝑛 3316682
 Birth
  Weight (g)3445.0 (510.9)3278.5 (462.8)3233.2 (421.6)0.0787
  Length (cm)50.7 (2.7)50.8 (2.6)49.8 (2.4)<0.000
 Age at visit, months3.7 (1.7)2.8 (1.5)6N.T.c

Breastfeeding score %b96.1 (16.9)81.0 (32.6)100<0.000
 W/H Z-scores0.16 (1.3)0.03 (1.4)−1.22 (1.2)<0.000
 H/A Z-scores−0.27 (1.5)0.52 (0.8)0.38 (1.3)0.001
 W/A Z-scores−0.22 (1.2)0.22 (0.9)−0.77 (0.7)<0.000

TCV-Hg, μg41.7 (29.8)42.4 (24.5)150<0.000
Infant’s hair Hg, μg·g−13.95 (1.8)1.85 (0.9)3.84 (5.5)<0.000

aNumber of fish meals a week; bbreastfeeding score = age of infant in days/breastfeeding days × 100; cN.T., not tested per se but as age-dependent variable for anthropometry and breastfeeding scores; W/H: weight for height; H/A: height for age, W/A: weight for age; TCV: uptake of mercury in thimerosal-containing vaccines.