Apple-shaped bodies linked to higher risk of cancer, dementia, psoriasis; researchers urge measures beyond BMI

New research and large-scale analyses are strengthening evidence that carrying excess weight around the midsection — commonly described as an “apple” body shape — is associated with higher risks of a range of illnesses, including heart disease, type 2 diabetes, bowel cancer, dementia, psoriasis and chronic kidney damage. Some researchers say the Body Roundness Index, which incorporates waist size, height and weight, may be a better clinical measure than body mass index.

Health survey data show abdominal obesity is common in the UK: at least 59 percent of men and 69 percent of women have waist circumferences generally exceeding 94 centimetres (37 inches) for men and 80 centimetres (31.5 inches) for women. Large waist size and excess belly fat have long been linked with cardiovascular disease and early death, and a growing body of evidence ties central fat distribution to many additional conditions.

A 20-year study of about 30,000 U.S. adults, reported in JAMA Network Open, found that a calculated Body Roundness Index (BRI) was a good predictor of all-cause mortality and that people with the roundest body shapes had the highest risk of dying from cancer and heart disease. Authors of that research argued the BRI — which uses waist size with height and weight — may better capture risk than BMI, which does not account for fat distribution.

Researchers and clinicians point to visceral fat and so-called ectopic fat as the biological mechanisms. Visceral fat lies deep in the abdomen around organs and secretes inflammatory proteins called cytokines. Ectopic fat accumulates in and around organs such as the liver, pancreas and heart; like visceral fat, it can provoke chronic inflammation and disrupt metabolic processes, raising blood-sugar levels and promoting insulin resistance.

A Johns Hopkins University study in 2020 reported apple-shaped people have higher risk of insulin resistance — a precursor to type 2 diabetes — even when overall body fat is similar to that of people with different fat distributions. A 2019 study published in the European Heart Journal warned that people of normal weight could still face elevated cardiovascular risk because of central fat distribution.

Recent specialty studies have broadened the list of conditions linked to abdominal fat. Researchers at King’s College London reported in May that abdominal fat was more strongly associated with psoriasis than total body fat after analysing data from more than 9,000 patients; the association held regardless of genetic predisposition. Inflammation driven by abdominal fat was cited as a likely pathway.

A July study from Monash University in Australia found that apple-shaped men were up to 38 percent more likely to develop dementia than men who were overweight overall but did not have prominent belly fat. The authors noted associations between central fat and shrinkage of the hippocampus, a brain region crucial for new memories. Inflammation is also a recognised contributor to cancer development, and an analysis of more than 500,000 people aged 40 to 69 published in the International Journal of Obesity last year reported that abdominal fat increased the risk of colorectal cancer regardless of a person’s overall weight.

Kidney function may also be influenced by fat distribution. A 2013 study from the University Medical Centre Groningen linked apple-shaped body composition with a higher risk of damaging elevations in pressure within the kidneys, potentially leading to long-term impairment.

Experts emphasise that abdominal fat can raise blood pressure and alter hormone signals. Andrew Scott, a senior lecturer in clinical exercise physiology at the University of Portsmouth who has published research on body-fat distribution, said fat in the midsection produces cytokines that trigger chronic inflammation and increases production of angiotensin, a hormone that constricts blood vessels and raises blood pressure.

The most direct response is reduction of abdominal fat. Evidence cited by researchers includes a 2019 study at the Albert Einstein College of Medicine that found women who reduced excess belly fat lowered their cardiovascular risk. Interventions shown to preferentially reduce visceral fat include high-intensity interval training (HIIT) and sprint interval training (SIT). A 2021 report from the Norwegian School of Sport Sciences found brief, repeated high-energy exercise sessions can significantly reduce proportions of belly fat even if overall body weight does not decline.

Scott and others also stress that modest, sustainable lifestyle changes can be effective. They point to improvements in cardiovascular fitness, moderation of carbohydrate intake and reductions in processed food, combined with regular brisk walking and bodyweight exercises, as practical approaches. Scott noted that five weeks of 30 minutes of brisk walking daily can produce measurable improvements in fitness and reductions in waist size for many people.

Some researchers are urging clinicians and public-health authorities to move beyond BMI as the sole measure of risk. The proposed BRI and routine measurement of waist circumference aim to identify people at elevated risk who might be missed by BMI alone.

Additional research continues to examine how body shape interacts with other risk factors. Height, for example, has been linked with distinct sets of risks: several studies have associated taller stature with higher overall cancer risk and an increased likelihood of atrial fibrillation, while shorter stature has been associated with greater risk of type 2 diabetes in some analyses.

Public-health guidance to monitor waist circumference and to adopt sustained lifestyle changes reflects the accumulating evidence that fat distribution, not only total body weight, matters for long-term health. Clinicians say routine waist measurement and attention to central adiposity could improve early identification of people at higher risk for multiple chronic diseases.