Adriëtte Oostvogels

206 Chapter 8 children with overweight in low/middle maternal education group had a higher mean BMI than those in the high education group, although not statistically significant for boys in the middle maternal education group. Discussion This study investigated socioeconomic and ethnic inequalities in BMI growth patterns to overweight at age 5-6 years, for boys and girls separately. No differences in BMI growth patterns to overweight were found when comparing European-origin children with non-European-origin children. However, overweight children in the low/middle SES group had a lower BMI during the first 2 years, an earlier adiposity rebound and a higher BMI at age 5-6 years compared to overweight children in the high SES group. Strengths & Limitations An important strength of this study was its longitudinal design with, on average, 13 standardized measurements at standard times performed by trained health care professionals in municipal Youth Health Care centers. However, this study had some limitations as well. First, we cannot rule out that there are no ethnic disparities in growth patterns to overweight in individual ethnic groups. Earlier research within the ABCD-study showed that from 0-3 years Surinamese children have lower BMIs and Moroccan and Turkish children have higher BMIs compared to the Dutch children, 29 while all three groups have higher percentages of overweight at age 5-6 years, 35,36 indicating that growth patterns to overweight might differ between specific non- European origin groups. Individual ethnic groups were not large enough to analyze separately and had to be combined into one non-European origin group. Differences within this non-European origin group directing in different directions might have led to the lack of ethnic disparities in growth patterns to overweight. Second, we might have underestimated the inequalities in BMI growth patterns, due to the lower prevalence of overweight in this study (girls: 14.6%; boys: 11.6%) compared to the prevalence nationwide (girls: 18.5%; boys: 14.6%). 37 Fewer children with overweight, results in lower power to generate differences in growth patterns.