Apple-shaped bodies tied to higher risks of cancer, dementia and psoriasis as experts call for measures beyond BMI

Researchers and clinicians are increasingly warning that an "apple" body shape—characterised by excess fat concentrated around the abdomen—is associated with higher risks of a wide range of illnesses, including cardiovascular disease, type 2 diabetes, bowel cancer, dementia, psoriasis and kidney damage. They say measures that account for waist size, such as the Body Roundness Index (BRI), may better predict disease risk than body mass index (BMI), which uses only height and weight.

Public-health data show the pattern is common. The Health Survey for England reports that at least 59 percent of men and 69 percent of women have a waist circumference above commonly used healthy thresholds (about 94 cm or 37 in for men and 80 cm or 31.5 in for women). Large-scale observational studies have repeatedly linked larger waist size and excess abdominal fat to heart disease, diabetes and premature mortality.

Researchers say the health risk associated with an apple shape stems from the behaviour of fat in and around the abdomen. Visceral fat, which lies deep in the abdominal cavity, and ectopic fat, which accumulates around and inside organs such as the liver, pancreas and heart, release inflammatory proteins and hormones that can damage organs and alter metabolism. That inflammatory environment is implicated in a range of conditions from insulin resistance to some cancers.

A 20-year study of roughly 30,000 U.S. adults published in JAMA Network Open found that a measure incorporating waist size with height and weight—the Body Roundness Index—was a strong predictor of all-cause mortality, and that those with the roundest bodies had the highest risk of dying from cancer and cardiovascular disease. Investigators have argued that BRI and other waist-based indices may identify high-risk people whom BMI alone would classify as normal-weight.

Separate research has tied abdominal fat specifically to several diseases. A King’s College London analysis of more than 9,000 people with psoriasis reported in the Journal of Investigative Dermatology found that central adiposity was more strongly associated with the risk of developing psoriasis than total body fat, and that this association persisted regardless of genetic predisposition. Psoriasis is an inflammatory skin condition that can also lead to arthritis when inflammation extends to the joints.

A study from Monash University published in Alzheimer’s & Dementia reported that men with prominent abdominal fat were up to 38 percent more likely to develop dementia than men who were overall overweight but did not carry excess weight centrally. The study found links between belly fat and shrinkage of the hippocampus, a brain region involved in forming new memories.

Evidence has also associated central adiposity with cancer risk. An analysis of more than 500,000 people aged 40 to 69 published in the International Journal of Obesity found that waist-fat was a risk factor for bowel cancer irrespective of a person’s overall body mass. Cancer researchers note inflammation as one biologic pathway by which abdominal and ectopic fat might promote tumour development.

Kidney function and blood pressure within the kidneys have been linked to body shape in earlier investigations. A 2013 study from the University Medical Centre Groningen found that people with greater abdominal fat were more likely to develop harmful increases in pressure inside the kidneys, which can strain small renal blood vessels and, over time, impair kidney function.

Researchers at Johns Hopkins in 2020 reported that people with an apple-shaped distribution of fat showed greater insulin resistance—a precursor to type 2 diabetes—than people with similar overall fat but different fat distribution. Other studies have warned that individuals of normal weight may nevertheless carry a high level of metabolically harmful abdominal fat and therefore remain at elevated cardiovascular risk.

Clinical scientists and exercise researchers stress that targeted lifestyle changes can reduce abdominal fat and lower risk. A 2021 trial reported by the Norwegian School of Sport Sciences in Frontiers in Physiology found that short, high-intensity interval training (HIIT) or sprint-interval training (SIT) sessions, practiced as little as three times a week, can reduce the proportion of abdominal fat even when overall body weight does not fall. Work from the Albert Einstein College of Medicine indicated that women who reduced their abdominal fat lowered their risk of cardiovascular disease.

Public-health experts emphasise that effective approaches do not require extreme diets or exhaustive regimens. Andrew Scott, a senior lecturer in clinical exercise physiology at the University of Portsmouth who has published on fat distribution and health, said improvements in cardiovascular fitness and moderation of processed carbohydrates can specifically reduce waist size over time. He advised practical steps such as brisk daily walking, stair climbing and simple bodyweight exercises, noting that modest, sustained lifestyle changes can yield measurable reductions in abdominal fat and improvements in fitness.

Height, too, has been associated with certain disease patterns in separate lines of research. Studies have found that taller stature correlates with modestly higher risk for some cancers, which researchers have variously attributed to greater cell numbers or exposure to growth factors during development. Conversely, some cardiovascular conditions and life-expectancy analyses have found different patterns associated with shorter height, illustrating that multiple anthropometric factors interact with genetics and environment to shape disease risk.

Clinicians say waist measurement is an accessible screening step to identify patients who may benefit from further metabolic assessment and targeted prevention. They note that waist-based indices are not perfect and that clinical judgment should combine measures of body shape, blood pressure, blood glucose, lipids and other risk markers. As research refines how best to quantify harmful fat distribution, experts recommend that individuals and clinicians pay attention to waist size alongside other established health metrics.