**3. Results**

#### *3.1. Descriptive Characteristic of Study Children*

A total of 311 children participated in the present study i.e., 160 were boys and 151 were girls. The average age was 4.67 years, ranging between 3 and 7 years (Table 1). The average body weight was 18.28 kg, the average height was 106 cm, and the average BMI was 16.6 kg/m2. Of 311 study children, 14.8% had low birth weight and 36.7% showed abnormal growth, based on Thailand Ministry of Public Health weight for height standards [19]. The geometric mean blood Pb level was 2.81 μg/dL, and 11.9% of children had blood Pb levels ≥5 μg/dL. The highest blood Pb level was 26.40 μg/dL, and 0.03 μg/dL was the lowest.


**Table 1.** Descriptive characteristics of study children.

Data for continuous variables are geometric means ± standard deviation (SD) values. a Abnormal growth is defined as underweight or overweight, based on the weight for height standard for Thai children; > +1.5 to > +3 SD (overweight), −1.5 SD to +1.5 SD (normal), < −1.5 SD to < −2 SD (underweight) (Nutrition Division Ministry of Public Health Thailand, 1999) [19]. *p* values ≤ 0.05 identify statistically significant differences between boys and girls. The Mann–Whitney U test was used to determine mean differences between boys and girls. The Chi-Square test was used to determine % differences between boy and girls.

The environmental and behavioral data showed that 14.5% of children lived near repair boatyards, whereas 23.5% had parents with an occupation in producing fishing nets at home. More than half of children consumed milk (64.3%) and seafoods (53.7%). There were no statistically significant differences between boys and girls with respect to all parameters/factors considered.

#### *3.2. Predictors of Blood Lead Levels* ≥ *<sup>5</sup>*μ*g*/*dL*

To screen for potential risk factors for high blood Pb levels in study children, we used age-adjusted logistic regression analysis. Table 2 presents the results of a final model that incorporated ten independent variables: gender, milk consumption, seafood consumption, signs of Pb toxicity, painted toys, use of painted ceramics, peeling of paint chips, living near a repair boatyard, and parent occupation. Of these ten incorporated variables, only two variables, namely parental occupation and milk consumption, were associated with the prevalence odds ratio (POR) for high blood Pb. Parental occupation in producing fishing cast nets with lead weights was associated with 17.54 (95%; CI: 7.093, 43.39) fold increase in POR for blood Pb levels ≥ 5μg/dL, compared with all other occupations (*p* < 0.001). In contrast, a child's milk consumption was associated with 61% reduction in the risk of having high blood Pb levels (POR = 0.393, 95%; CI: 0.166, 0.931; *p* = 0.034).



POR = Prevalence odds ratio. High blood Pb is defined as blood Pb levels ≥ 5μg/dL. The POR for high blood Pb was derived from logistic regression in which high blood Pb was a categorical dependent variable. Independent variables were listed in the first column. \* *p* ≤ 0.05 identify the variable as a significant risk factor or predictor for high blood Pb levels.

#### *3.3. Predictors of Abnormal Growth*

We used also age-adjusted logistic regression to determine potential effects of high blood Pb levels on children's growth, defined as overweight or underweight in accordance with weight and height standards for Thai children. Table 3 presents the results of such analysis that incorporated seven independent categorical variables, including high blood Pb, milk and seafood consumptions, use of painted ceramics, living near a repair boatyard, and playing with painted toys. High blood Pb was associated with 2.042 (95%; CI: 0.999, 4.174) fold increase in POR for abnormal growth (*p* = 0.050). Seafood consumption was associated with 1.713 (95%; CI: 1.037, 2.831) fold increase in POR for abnormal growth (*p* = 0.036). In contrast, milk consumption was associated with 43% reduction in the risk of having abnormal growth (POR 0.573, 95%; CI: 0.337, 0.976; *p* = 0.040).




**Table 3.** *Cont.*

POR = Prevalence odds ratio. a Abnormal growth is defined as underweight or overweight, based on weight for height standard for Thai children; > +1.5 SD to > +3 SD (overweight), −1.5 SD to +1.5 SD. (normal), < −1.5 SD to < −2 SD (underweight) (Nutrition Division Ministry of Public Health Thailand, 1999) [19]. \* *p* ≤ 0.5 identify significant associations between abnormal growth and variables/factors listed in the first column.
