Dietary habits of school-age children and its associations with blood pressure level in Beijing, China / 中华预防医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To study the dietary habits of school-age children in urban and rural districts and their association with blood pressure levels in Beijing, China.</p><p><b>METHODS</b>A stratified, randomly clustered sampling design was used, 29 primary and secondary schools from four urban districts and three rural districts in Beijing were randomly selected in 2004. 20 638 children aged 6-18 years old were surveyed, and 19 072 of them provided completed usable data. The weight, height and blood pressure of the subjects were measured according to standard method.10 food-groups' information was collected by a semi-quantitative food frequency questionnaire. The relationship between different dietary habits and the blood pressure levels in school children was analyzed by multiple linear regression model.</p><p><b>RESULTS</b>The prevalence of obesity among children in urban area (12.2%, 1 218/9 984) was higher than that in rural area (6.7%, 609/9 088) (χ(2) = 4.62, P < 0.05) , whereas the prevalence of hypertension among children in urban area (8.0%, 799/9 984) was lower than that in rural area (8.9%, 809/9 088) (χ(2) = 167.32, P < 0.05) . The diastolic blood pressure (DBP) among children was (65.7 ± 8.6) mmHg (1 mmHg = 0.133 kPa) in urban area and (67.0 ± 8.7) mmHg in rural area, respectively (F = 86.44, P < 0.05) , and the systolic blood pressure (SBP) among children was (103.4 ± 12.2) mmHg in urban area and (104.3 ± 11.6) mmHg in rural area, respectively (F = 11.33, P < 0.05) . Factor analysis revealed 4 dietary habits labeled prudent habit, protein habit, high-fat and high-calorie habit and vegetables and fruits habit. The 4 dietary habits' variance contribution rate respectively was 24.7%, 14.6%, 14.0%, 8.9%, and the 4 dietary habits totally reflect 62.2% characteristics of the 10 food-groups.In urban area, prudent habit was inversely associated with DBP (β' = -0.026, P < 0.05) , Protein habit was inversely associated with both children's SBP (β' = -0.018, P < 0.05) and DBP (β' = -0.030, P < 0.05) .In rural area, prudent habit was associated with children's SBP (β' = -0.050, P < 0.05) and DBP (β' = -0.039, P < 0.05) .</p><p><b>CONCLUSIONS</b>The dietary habits of school age children varied by sociodemographic characters in Beijing. The prudent habit and protein habit may decrease the children's blood pressure levels.</p>