WASHINGTON — The number of US states where at least 35 percent of residents are obese rose to 16 last year, with notable ethnic and racial disparities, new data from the Centers for Disease Control and Prevention (CDC) showed Wednesday.

The states are mainly in the country’s South and Midwest, and the total figure is up from nine in 2018 and 12 in 2019. The research comes via self-reporting from telephone surveys, and defines obesity as a body mass index BMI of 30 and over.

Having obesity puts people at risk for many other serious chronic diseases including heart disease, stroke, type 2 diabetes, some types of cancer and poorer mental health.

CDC research has shown obesity triples the risk of Covid-19 hospitalization, because the condition is linked to impaired immune function. It also decreases lung capacity and reserve and can make ventilation more difficult.

The 16 states were Alabama, Arkansas, Delaware (new this year), Indiana, Iowa (new this year), Kansas, Kentucky, Louisiana, Michigan, Mississippi, Ohio (new this year), Oklahoma, South Carolina, Tennessee, Texas (new this year), and West Virginia.

The CDC also studied combined data from 2018 to 2020 to understand racial differences.

No states had obesity prevalence at above 35 percent among Asian residents — though some studies have shown health risks linked to obesity may occur at a lower BMI among Asians.

Seven states had a high obesity prevalence for white residents, 22 states had a high obesity prevalence for Hispanic residents, and 35 states and the District of Columbia had a high obesity prevalence among Black residents.

Obesity prevalence decreased by education. Adults without a high school degree or equivalent had the highest level of self-reported obesity (38. 8 percent), with college graduates the lowest (25.0 percent).

Adults aged 18-24 years had the lowest self-reported obesity (19.5%) compared to adults aged 45-54 years (38.1 percent).

The CDC encouraged people to talk to their healthcare providers about their body mass index, family history of chronic disease, current lifestyle, and health risks.