Association of waist circumference with blood pressure and familial dietary habits in preschool children: a cross-sectional study in northeastern China

Background Childhood obesity increases the risk of elevated blood pressure (BP) in children. Body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR) are traditional obesity indices, but the extent to which these indices are associated with elevated BP in childhood remains debatable. Moreover, the familial dietary environment plays an important role in obesity, so it is necessary to determine the most relevant dietary factors for childhood obesity to prevent elevated BP. Our study aimed to identify the obesity indices that are most closely associated with elevated BP and then to determine the independent familial dietary factors for those obesity indices. Method A total of 605 children aged 2 to 6 years, as well as their parents, were involved in this study. The weight, height, WC and BP of the children were measured. Information on familial environments was obtained by questionnaires completed by the parents. BMI, WC and WHtR were standardized into z scores, and categorical variables of these three obesity indices were defined as BMI Category, WC Category and WHtR Category. Logistic regression was used to analyse the associations between all obesity indices and elevated BP. Multivariate linear regression and logistic regression were used to determine the independent factors for obesity indices. Results The obesity indices that were most closely associated with elevated BP were WC and WC Category. Parental BMI, birth weight, eating wheat as a staple food, appetite, eating speed, snacking while watching TV, parental encouragement to eat a diverse assortment of foods and drinking milk were independently associated with WC in both males and females. The risk of abdominal obesity increased 1.375 times in males and 1.631 times in females if appetite increased one level. If eating speed increased one level, the risk of abdominal obesity increased 1.165 times in males and 0.905 times in females. Females who drank milk more than 6 times per week had a 0.546 times lower risk of abdominal obesity. Conclusion WC was an anthropometric parameter more closely associated with elevated BP. In addition to genetics, some familial dietary factors involving eating preference, eating habits and parental feeding practice were independently associated with WC and abdominal obesity in preschool children.