Children from low-income families tend to be less physically fit and at higher risk of obesity than children from higher-income families, a Johns Hopkins Bloomberg School of Health study finds. The association persists regardless of race or ethnicity.

The study analysed data from 1.6 million fifth-, seventh-, and ninth-grade California children who took a physical fitness test from 2010 through 2012. Researchers tested whether low family income was associated with physical fitness level or obesity prevalence. Fitness scores were measured on a scale from 0 (least healthy) to 6 (most healthy). Researchers found that the average fitness score was 4.45. The prevalence of obesity was 20.3 percent, and 56 percent of children were classified as having a low family income.

"This information is relevant for targeting policies and programs aimed at improving the fitness levels and decreasing the obesity risk of children," the researchers conclude.

Research: Associations Between Family Income and Children's Physical Fitness and Obesity in California, 2010-2012, Jessica C. Jones-Smith, PhD, MPH, RD, Preventing Chronic Disease, published 12 February 2015.