Young Alaska Native children are far more likely to be obese than their non-Native counterparts, and family strife is a major factor that puts those young children at risk for obesity, a new study finds.

Among Alaska Native 3-year-olds, 42.2 percent were found to be obese, compared to 24.9 percent of all Alaska 3-year-olds, said the study, published in the journal PLOS ONE. Obesity rates for these young children were highest in the north and southwest parts of the state; 51.6 percent of Alaska Native 3-year-olds in those regions were found to be obese.

The study, possibly the first to analyze obesity rates for such young children in specific parts of Alaska, revealed a dramatic contrast between Native and non-Native health, said lead author Janet Wojcicki, an assistant professor of pediatrics at the University of California, San Francisco.

"One of the things that was really stunning was the incredibly higher prevalence in Alaska Native children," she said. "If more than 50 percent are obese in the north and southwest parts of the state, that's high."

The high rate for rural Alaska Native children compares to an obesity rate of just less than 20 percent for non-Native Alaska 3-year-olds, according to the study.

The study uses data collected from the Alaska Pregnancy Risk Assessment Monitoring System, a program that has been in place since 1990. Study authors compared PRAMS data collected in 2005 and 2006 to follow up data collected in 2006 and 2007 from the Alaska Childhood Understanding Behaviors Survey.

Those statewide surveys provided the data used to tease out the various risk factors associated with obesity in Native and non-Native 3-year-olds.

The study used Centers for Disease Control growth charts as the standard for body mass index, the measurement generally used to define obesity.

Some obesity risk factors -- for Native and non-Native children -- are clearly linked to nutrition.

One is consumption of sugary drinks, which flood into rural Alaska villages and have long been blamed in part for high rates of obesity among Alaska Native children. That blame is appropriate, the study suggests: 57.5 percent of Alaska Native children who drank two or more cups of soda per day were obese as 3-year-olds, the study found.

Absence or brevity of breastfeeding was also a risk factor, while longer breastfeeding during infancy was associated with less obesity for both Native and non-Native 3-year-olds, the study found.

But there were some obesity risk factors that might seem less obvious -- including exposure to family violence for Native children and poverty for non-Native children, according to the study.

Alaska Native children who witnessed domestic violence or abuse had an especially high propensity to be obese, with a 59.3 percent rate found among 3-year-olds. Being a witness to such events was the most powerful risk factor among Alaska Native children, the study found.

That was a risk factor for non-Native children in Alaska, elevating the likelihood of obesity, but low family income and maternal pre-pregnancy obesity were higher risk factors for those children, the study found.

The findings suggest that combating obesity among Alaska Native children will be more difficult than simply cutting calories.

"Future obesity interventions with Alaska Native children, in addition to focusing on diet and exercise alone, may take into consideration the psychosocial context of the family so as to potentially reduce obesity risk," the study said.

The strong association between domestic violence and childhood obesity is logical when examined closely, the study authors said.

Households affected by domestic violence might also suffer from more disarray, which can affect meal planning and preparation, Wojcicki said.

Still, the experience of witnessing domestic violence and abuse causes its own stress and coping mechanisms can affect eating habits, Wojcicki said. While babies subjected to stress lose weight and suffer from "failure to thrive," older children -- and adults -- are known to turn to comfort foods, many of which are sugar-laden, she said.

"We definitely know that stress impacts eating and weight gain," she said.

Effects of such stress probably go beyond dietary behavior, said another study co-author, Dr. Peter de Schweinitz, a Fairbanks physician who works with the Tanana Chiefs Conference.

"In effect, stress has a very definite physiological impact on the body's metabolism," he said.

Chronic stress causes a signal from the brain to the adrenal gland that results in more production of the hormone cortisol, de Schweinitz said. Cortisol -- like adrenaline -- is released by the gland to help the body cope with stress. Cortisol puts large amounts of sugar into the bloodstream.

"Then your body will store that sugar," he said -- and usually around the abdomen.

Compared to the sometimes grave results of domestic violence, obesity might not rise to the top of the list of concerns for rural Alaska Natives. And compared to other dire social problems like alcohol abuse and suicide, "Sugar consumption falls lower on the spectrum," he said.

Still, it is a serious health issue, he said. He cites research by Dr. Rob Lustig, a professor of pediatrics at the University of California, San Francisco, that examines the U.S. obesity epidemic, the growing levels of sugar consumption and the effects that sugar has on the liver. Lustig has become famous for his declaration that sugar is the "alcohol of the child."

For rural Alaska Natives, de Schweinitz said, a combination of food supply and drinking water problems contribute to the high levels of sugar consumption.

But there are also sincere efforts to change that pattern, he said.

Through a Tanana Chiefs Conference health program, for example, store owners in the interior villages of Tanana and Huslia have been studying ways to reduce sales of sugary drinks and encourage consumption of bottled water or other healthier alternatives, he said.

Village residents of all ages are keen on improving their diets, and any fresh fruits or vegetables -- though expensive to supply and difficult to store for long periods -- are popular, de Schweinitz said.