The obesity epidemic continues to threaten the health and well-being of millions of adults and youth in the United States. This month’s Research Roundup highlights three studies from Kaiser Permanente research centers that explore causes, outcomes and trends related to maternal and childhood obesity.
Obesity Rates Are Falling Among Southern California Youth
Childhood obesity is a serious issue in the United States, with rates having more than doubled in children and quadrupled in adolescents in the past 30 years. However, a new study from Kaiser Permanente’s Department of Research & Evaluation in southern California has found that the prevalence of overweight and obese youth in that region has declined in recent years.
This study is based on the ongoing Children’s Health Study, which includes information on more than 1.3 million Kaiser Permanente members ages 2 to 19 in southern California. Findings, published in the Journal of Pediatrics, indicate that between the years 2008 and 2013, the prevalence of overweight and obesity in boys and girls among all ages, races, and socioeconomic groups declined significantly. Notably, however, it was less pronounced among girls, adolescents, and Hispanic and African American youth. Lead author Corinna Koebnick, PhD, notes that obesity prevention efforts – such as school snack and sugary beverage standards set by the state government in the last decade – may be impacting overall obesity rates. Because declining obesity trends are not uniform across all youth, however, additional programs and solutions addressing childhood obesity must be targeted at these groups.
Early Puberty in Girls Linked to Maternal Obesity and Diabetes
Over the past few decades, researchers have been following and trying to understand a trend of earlier puberty onset among girls in the United States. Early puberty has been shown to increase the risk of a variety of adverse health outcomes including obesity, type 2 diabetes, polycystic ovarian syndrome, and cancer. A new study from Kaiser Permanente’s Division of Research in northern California indicates that obesity and gestational diabetes in mothers can lead to early puberty in their daughters.
This study builds on the Cohort Study of Young Girls’ Nutrition, Environment, and Transitions (CYGNET), a long-term study of puberty development in girls that followed 421 girls and their mothers, all members of Kaiser Permanente Northern California, from 2005 through 2012. This new study finds that in utero exposure to obesity and diabetes increases a daughter’s risk of early puberty regardless of the daughter’s weight.
“Very few previous studies have examined the association between maternal pregnancy and pre-pregnancy factors and the timing of puberty in daughters. Understanding what causes earlier onset of puberty is important in designing prevention strategies,” explains epidemiologist and lead author, Ai Kubo, MPH, PhD. Strategies to decelerate the trend of early puberty may be realized, the study suggests, through upstream interventions to manage obesity among women who are pregnant or planning to become pregnant.
Weight Gain and High Blood Sugar in Pregnant Women “Imprints” Baby for Childhood Obesity
A recent study from the Kaiser Permanente Center for Health Research sheds new light on risk factors related to childhood obesity. Researchers found that children whose mothers gained excessive weight or had elevated blood sugar during pregnancy were more likely to become overweight or obese in their first ten years of life. This is the first study to show an increased likelihood of childhood obesity among babies born at a normal weight (5.5 to 8.8 pounds) to mothers with excessive weight gain or gestational diabetes during pregnancy.
The study, published in the Maternal and Child Health Journal, followed 24,141 mothers and normal birth weight babies born between 1995 and 2003 in Oregon, Washington, and Hawaii. Children of women who gain over 40 pounds – the maximum recommended weight gain during pregnancy according to the Institute of Medicine – were 15 percent more likely to be overweight or obese between the ages of 2 and 10, compared to children whose mothers experienced normal weight gain. And children whose mothers had gestational diabetes were 30 percent more likely to be overweight or obese between the same ages. Teresa Hiller, MD, MS, lead author of the study, explains. “When women have elevated blood sugar and gain excess weight during pregnancy, it seems to change the baby’s metabolism to ‘imprint’ the baby for childhood obesity.”
A variety of factors post-birth can contribute to the likelihood of a child becoming overweight or obese; however, this study highlights that it is important to pay attention to what happens in utero as well. Dr. Hillier adds, “We need to intervene during the mom’s pregnancy to help her with nutritional and lifestyle changes that will result in healthy weight gain, healthy blood sugar and ultimately, healthy children.”
Kaiser Permanente continues to study risk factors and trends related to maternal and childhood obesity. For more information on these studies and other Kaiser Permanente research, please contact Albert Martinez at Albert.Martinez@kp.org.