McDonald’s (NYSE: MCD) is the largest fast-food hamburger chain in America with nearly 16,000 locations nationwide. In areas that have the most McDonald’s per capita, the population tends to have higher rates of obesity and heart disease. While a direct connection cannot be made between McDonald’s and negative health outcomes, areas with clusters of fast-food restaurants of any type typically have less healthy populations.

To identify the states with the most and least McDonald’s per capita, 24/7 Wall St. reviewed the concentration of McDonald’s restaurants in every state per 100,000 residents with data from restaurant reviewer and data compiler Menuism. Ohio has the highest concentration of McDonald’s with 7.1 locations per 100,000 people. This is more than twice the amount in New Jersey, the state with the lowest concentration of McDonald’s.

The association between the obesity rate and the concentration of McDonald’s restaurants in an area seems to be stronger than with other fast food chains. Of the 10 states with the highest concentration of major fast food restaurants, excluding McDonald’s, five have obesity rates higher than the nation. However, of the 10 states with the highest concentration of McDonald’s, all 10 have higher obesity rates than the nationwide rate.

Areas that have higher concentrations of McDonald’s and poorer health outcomes tend to have other traits that can lead to poor health. For example, areas with high concentrations of McDonald’s tend to be poorer. In all but one of the 10 states with the most McDonald’s, the typical household earns less than the national annual median household income.

2. Michigan

> No. of McDonald’s:6.4 (per 100,000 people)
> Obesity rate: 31.4% (10th highest)
> Pct. consuming vegetables less than daily: 23.2% (23rd highest)
> Median household income: $49,847 (20th lowest)

Many other traits related to poor health are common among states with the most McDonald’s. For one, residents tend to engage in less healthy behaviors. For example, adults report being less physically active, and the smoking rates are higher in these states. Nine of the 10 states with the most McDonald’s outlets per capita have a higher smoking rate than the nationwide rate.

Whether unhealthy residents in an area are McDonald’s customers, or whether consuming fast food like McDonald’s hamburgers actually leads to such poor health outcomes, is difficult to determine with confidence. Nonetheless, residents in areas with high concentrations of McDonald’s locations tend to be less healthy than in areas with a lower concentration.

To identify the states with the greatest concentration of McDonald’s restaurants, 24/7 Wall St. reviewed location data for McDonald’s, Burger King, Wendy’s (NASDAQ: WEN), Taco Bell, KFC — which is a division of Yum! Brands (NYSE: YUM), Subway, Starbucks (NASDAQ: SBUX), Pizza Hut, Dunkin’ Donuts (NASDAQ: DNKN), and Chick-fil-A from Menuism. Population data, income, educational attainment rates, and poverty statistics are from the U.S. Census Bureau’s 2014 American Community Survey (ACS). Self reported obesity rates are from County Health Rankings & Roadmaps, a Robert Wood Johnson Foundation and University of Wisconsin Population Health Institute joint program. We also considered self-reported adult consumption of fruits and vegetables from the Centers for Disease Control and Prevention’s 2013 State Indicator Report on Fruits and Vegetables.

Click here to see the states with the most McDonald’s.