Members of wholesale retailers such as Sam’s Club and Costco are more likely to be obese. That’s among the findings of a recent study of economic variables on obesity.

The study, submitted recently to the National Bureau of Economic Research, examined 27 variables to determine their affect on body mass index and obesity. It was conducted by researchers from several universities, including the University of Louisville.

Josh Pinkston, a research in the University of Louisville’s College of Business, said an increase in the number of superstore groceries and warehouse clubs are the leading causes of the rise in obesity.

“It’s certainly an easy conclusion that people aren’t responding to the increased convenience and decreased cost of food in a balanced manner or at least in a manner that’s good for long-term health,” he said.

The researchers tied those types of stores to increases in body mass index and severe obesity, as well as an increase in the prevalence of obesity. The researchers found similar results for restaurants.

“Restaurants obviously save people time in terms of cooking and cleaning,” he said. “The warehouse clubs might be able to sell foods that can be consumed in a more convenient manner, but they also sell food at lower prices.”

Researchers also found the decline in blue collar employment contributed to 6 percent of the rise of obesity, and increased food stamp expenditures explained about 8 percent of the rise in severe obesity.

Surprisingly, smoking bans don’t have a significant affect on obesity, according to the study. Pinkston said it only attributed to the average rise in BMI by 4 percent.