Wisconsin’s obesity rate appears to be higher than previously thought, according to new data released in December 2016.

The earlier estimate was that the obesity rate among adults in the state was 31 percent, but new numbers from the Survey of the Health of Wisconsin find that nearly 40 percent of Wisconsin adults are obese.

In addition, the state’s obesity rate is about 4.5 percent higher than the national average.

Dr. Patrick Remington, professor and associate dean of public health at the UW School of Medicine and Public Health, said the 9 percent difference was discovered thanks to a better survey methodology.

“The big reason is that almost all of the previous estimates of rates of overweight and obesity have been gotten by telephone surveys, and we know from recent experience that telephone surveys aren’t always perfectly accurate,” he said.

In fact, people on the telephone tend to underreport their weight and overreport their height, especially men, said Remington.

“So when you actually do sampling, which is what the Survey of the Health of Wisconsin does, and go into people’s homes and do physical exams, and also improve the response rates … we find that we pretty significantly underestimated the actual measured percent of obesity in the state,” Remington said.

Higher rates of obesity are related to considerable health care costs and providesall kinds of challenges to people as they gain weight, from arthritis to diabetes. The solution, said Remington, is making sure people are immersed to make better decision about their health.

“The best thing to do is provide environments, all the way to schools to workplaces to communities, that let people be active and eat a healthy diet so we don’t have to be looking at such high numbers in the community,” he said.

The discovery coincides with the recent news that for the first time in decades, life spans in the United States have dropped slightly. Higher obesity rates won’t help reverse that trend.

“For the first time ever we’ve seen a decline in life expectancy,” Remington said. “Although it’s a very small decline, it really doesn’t look good for the future because we haven’t as a population been able to turn the obesity epidemic around.”