Faster weight gain in infancy predicts higher blood pressure in early childhood

Accelerated gains in age- and sex-standardized BMI in early and late infancy are each associated with higher levels of systolic and diastolic blood pressure at ages 3 to 6 years, independent of standardized BMI at birth, according to study findings published in the International Journal of Obesity.

"Blood pressure in childhood tracks into adulthood, and persistent exposure to elevated levels in childhood and adulthood is associated with increased risk [for] carotid artery atherosclerosis," Catherine S. Birken, MD, MSc, FRCPC, staff pediatrician at the Hospital for Sick Children in Toronto and associate professor in the department of pediatrics at the University of Toronto, and colleagues wrote. "Prevalence estimates from the National Health and Nutrition Examination Survey have reported that one in 10 children [has] elevated BP ( 90th percentile). Identifying risk factors associated with BP in early childhood ... is important to develop targets for cardiovascular disease prevention."

Birken and colleagues analyzed data from 2,502 children with repeated measures of sex-standardized BMI (zBMI) and BP collected as part of the Applied Research Group for Kids (TARGet Kids!), an ongoing, longitudinal study conducted during well-child visits across 13 primary care practices in Toronto and Montreal. For stage 1 of the study, researchers modeled repeated measures of zBMI at ages 0-3 months, 3-18 months and 18-36 months to generate rates of zBMI gain for each child. For stage 2, researchers modeled the association between rates of zBMI gain with BP in children aged 36-72 months.

Researchers found that each 1 standard deviation unit faster rate of zBMI gain at ages 0-3 months was associated with a 0.59 mm Hg higher systolic BP at ages 36-72 months (P <.001) in analyses adjusted for multiple factors, including age and height at BP measurement, sex, family income, breastfeeding duration and parental history of hypertension. A 1-SD unit faster rate of zBMI gain at ages 3-18 months was associated with a 0.74 mm Hg higher systolic BP (P .001) in adjusted analyses, whereas the same faster rate of zBMI gain at ages 18-36 months was not associated with an elevated systolic BP after adjustment, according to researchers.

Results were similar in analyses assessing the association between rate of zBMI gain and diastolic BP. Each 1 standard deviation unit faster rate of zBMI gain at ages 0-3 months was associated with a 0.28 mm Hg higher diastolic BP (95% CI, 0.04-0.53) at ages 36-72 months in adjusted analyses, whereas a 1-SD unit faster rate of zBMI gain at ages 3-18 months was associated with a 0.44 mm Hg higher diastolic BP (95% CI, 0.2-0.68), according to researchers.

Results were similar when stratified by sex. There was no association between zBMI at birth and systolic or diastolic BP at ages 36-72 months.

In adjusted analyses, researchers found that children with a 1-SD unit faster rate of zBMI gain at ages 0-3 months were 55% more likely to have elevated systolic BP in early childhood (OR = 1.55; 95% CI, 1.18-2.04). Children with a similar zBMI gain at ages 3-18 months were 42% more likely to have elevated systolic BP in early childhood (OR = 1.42; 95% CI, 1.07-1.89). A 1-SD unit faster gain in zBMI at ages 18-36 months was associated with a 22% chance of elevated diastolic BP in early childhood (OR = 1.22; 95% CI, 1.04-1.44) but not with a rise in systolic BP, according to researchers.

The researchers noted that birth weight modified the relationship between accelerated zBMI gain at ages 3-18 months and systolic BP (P = .02 for interaction), with the strongest positive relationship observed among children with low birth weight. Maternal obesity status did not modify the relationship between zBMI at birth or rates of zBMI gain during any period with BP.

"We observed a stronger association between rapid growth during [ages] 3-18 months with BP in children born with low birth weight and therefore highlight a developmental window to prioritize interventions for children in this risk group," the researchers wrote. "Further studies are needed to replicate our observations and to identify interventions to promote growth with optimal short-term and long-term health outcomes on CVD during these distinct periods of early life." - by Regina Schaffer

Disclosures: Birken reports a research grant from the Centre for Addiction and Mental Health Foundation. Please see the study for all other authors' relevant financial disclosures.

Accelerated gains in age- and sex-standardized BMI in early and late infancy are each associated with higher levels of systolic and diastolic blood pressure at ages 3 to 6 years, independent of standardized BMI at birth, according to study findings published in the International Journal of Obesity.

"Blood pressure in childhood tracks into adulthood, and persistent exposure to elevated levels in childhood and adulthood is associated with increased risk [for] carotid artery atherosclerosis," Catherine S. Birken, MD, MSc, FRCPC, staff pediatrician at the Hospital for Sick Children in Toronto and associate professor in the department of pediatrics at the University of Toronto, and colleagues wrote. "Prevalence estimates from the National Health and Nutrition Examination Survey have reported that one in 10 children [has] elevated BP ( 90th percentile). Identifying risk factors associated with BP in early childhood ... is important to develop targets for cardiovascular disease prevention."

Birken and colleagues analyzed data from 2,502 children with repeated measures of sex-standardized BMI (zBMI) and BP collected as part of the Applied Research Group for Kids (TARGet Kids!), an ongoing, longitudinal study conducted during well-child visits across 13 primary care practices in Toronto and Montreal. For stage 1 of the study, researchers modeled repeated measures of zBMI at ages 0-3 months, 3-18 months and 18-36 months to generate rates of zBMI gain for each child. For stage 2, researchers modeled the association between rates of zBMI gain with BP in children aged 36-72 months.

Researchers found that each 1 standard deviation unit faster rate of zBMI gain at ages 0-3 months was associated with a 0.59 mm Hg higher systolic BP at ages 36-72 months (P <.001) in analyses adjusted for multiple factors, including age and height at BP measurement, sex, family income, breastfeeding duration and parental history of hypertension. A 1-SD unit faster rate of zBMI gain at ages 3-18 months was associated with a 0.74 mm Hg higher systolic BP (P .001) in adjusted analyses, whereas the same faster rate of zBMI gain at ages 18-36 months was not associated with an elevated systolic BP after adjustment, according to researchers.

Results were similar in analyses assessing the association between rate of zBMI gain and diastolic BP. Each 1 standard deviation unit faster rate of zBMI gain at ages 0-3 months was associated with a 0.28 mm Hg higher diastolic BP (95% CI, 0.04-0.53) at ages 36-72 months in adjusted analyses, whereas a 1-SD unit faster rate of zBMI gain at ages 3-18 months was associated with a 0.44 mm Hg higher diastolic BP (95% CI, 0.2-0.68), according to researchers.

Results were similar when stratified by sex. There was no association between zBMI at birth and systolic or diastolic BP at ages 36-72 months.

In adjusted analyses, researchers found that children with a 1-SD unit faster rate of zBMI gain at ages 0-3 months were 55% more likely to have elevated systolic BP in early childhood (OR = 1.55; 95% CI, 1.18-2.04). Children with a similar zBMI gain at ages 3-18 months were 42% more likely to have elevated systolic BP in early childhood (OR = 1.42; 95% CI, 1.07-1.89). A 1-SD unit faster gain in zBMI at ages 18-36 months was associated with a 22% chance of elevated diastolic BP in early childhood (OR = 1.22; 95% CI, 1.04-1.44) but not with a rise in systolic BP, according to researchers.

The researchers noted that birth weight modified the relationship between accelerated zBMI gain at ages 3-18 months and systolic BP (P = .02 for interaction), with the strongest positive relationship observed among children with low birth weight. Maternal obesity status did not modify the relationship between zBMI at birth or rates of zBMI gain during any period with BP.

"We observed a stronger association between rapid growth during [ages] 3-18 months with BP in children born with low birth weight and therefore highlight a developmental window to prioritize interventions for children in this risk group," the researchers wrote. "Further studies are needed to replicate our observations and to identify interventions to promote growth with optimal short-term and long-term health outcomes on CVD during these distinct periods of early life." - by Regina Schaffer

Disclosures: Birken reports a research grant from the Centre for Addiction and Mental Health Foundation. Please see the study for all other authors' relevant financial disclosures.