A study published today in the journal Neruology has found that people who are both obese and metabolically abnormal can expect to have their metal capabilities degrade at a faster rate than those who don’t suffer similar health issues.

The study, a Whitehall cohort study, looked at 6,401 adults between the ages of 39 and 63 years old. Those labeled obese for the purposes of the study had a body mass index (BMI) of over 30 kg/m^2. A metabolic abnormality was defined as having 2 or more of the following conditions: high blood pressure, diabetes, high colesterol, or high triglycerides. Cognitive tests measuring the test subjects’ memory, reasoning, semantic, and phonemic fluency abilities were given at 5-year intervals.

The fastest cognitive decline was seen in subjects who had both obesity and metabolic abnormalities. For test subjects who were metabolically normal, whether obese or not, cognitive decline was similar. It is only the combination of the two factors that the researchers found to increase cognitive decline.

The Whitehall studies are large British studies which investigate the health of humans throughout their life. The first Whitehall study examined mortality rates for male British Civil Servants. The current Whitehall study is ongoing, and investigates occupational and social influences on health.

Though this study was performed on British citizens, obesity is on the rise in the U.S. Given that obesity has been linked to some of the metabolic abnormality factors listed in the study (such as diabetes), those with a high BMI but little muscle may want to begin worrying about their mental health as well as physical.