Abstract and Introduction
Abstract
Objectives To evaluate links between the volume of milk consumed and weight and height status in children aged 4 and 5 years.
Design We analysed data from 8950 children followed up as part of the Early Childhood Longitudinal Survey, Birth cohort, a nationally representative cohort of children. We used linear and logistic regression to assess associations of daily servings of milk intake at age 4 years with z-scores of body mass index (BMI), height and weight-for-height at 4 and 5 years, adjusted for sex, race/ethnicity, socioeconomic status and type of milk consumed.
Results Among children who drank milk at age 4 years, higher milk consumption was associated with higher z-scores of BMI, height and weight-for-height at 4 years (all p<0.05). This corresponded to differences between children drinking <1 and ≥4 milk servings daily of approximately 1 cm in height and 0.15 kg in weight. By age 5 years, only the association with height remained significant (p<0.001). At 4 years, children drinking ≥3 servings of milk daily were more likely to be overweight/obese (BMI≥85th percentile) than those drinking 0.5–2 servings of milk daily (adjusted OR 1.16 (95% CI 1.02 to 1.32) p=0.02).
Conclusions In a cohort of children at age 4 years, the volume of milk consumed was associated with higher weight status and taller stature, while at 5 years, higher milk consumption continued to be associated with taller stature. Given higher odds of overweight/obesity with milk consumption ≥3 servings daily, this study supports current American Academy of Pediatrics recommendations that pre-school children consume two milk servings daily.
Introduction
Childhood linear growth and weight gain are important markers of nutritional status and overall health. However, the recent epidemic of early childhood obesity highlights sequelae of excess weight gain such as hypertension, cardiovascular disease and type 2 diabetes in adulthood. Thus, there is a need to establish effective weight control strategies for preschool-aged children.
One possible intervention is decreasing high-energy beverage consumption, including milk, which contains 83–149 calories per serving. The American Academy of Pediatrics (AAP) and the American Dietetic Association recommend two servings (2 cups or 573 mL) of milk daily for children aged 2–8 years. However, the basis for these recommendations is unclear. Data linking the quantity of milk consumption to weight status of preschoolers are limited and conflicting. Several studies of beverage consumption in preschoolers and school-aged children reported no relationship between the amount of milk intake and body mass index (BMI) z-score; three studies reported lower BMI z-scores among children with higher milk consumption (or less body fat with higher total dairy) and another study reported higher BMI increases in children drinking >3 servings of milk daily.
Complicating the matter is the potential effect of milk consumption on linear growth. Multiple studies (but not all) found taller stature in individuals who drank more milk during different periods of childhood, though this has not yet been observed in preschoolers. Following the physiological nadir of BMI at approximately 4–5 years of age, increases in linear growth are associated with physiological increases in BMI, raising the potential that milk-related increases in BMI could be related to increasing linear growth. Data are lacking regarding the association between milk consumption and weight-for-height, leaving unclear the relationship between milk consumption and unhealthy weight status.
Our goal was to evaluate relationships between the amount of milk consumed and the z-scores of BMI, height and weight-for-height among a large cohort of children aged 4–5 years. These children were studied as part of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), a prospective, representative survey of US children. Our hypotheses were that higher quantities of milk consumed would be associated with higher z-scores for BMI and height and a greater increase in BMI z-score over time.