Sian Claire Owen, medical journalist for Cardio Debate, UK

New research has debunked the controversial hypothesis that obesity has some protective effects in certain individuals, and some obese people live longer than those of normal weight.

A population-based study, run by researchers at Northwestern University, Illinois, US, analysed 190,672 in-person examinations (mean age 46.0 years for men, and 58.7 years for women), and found that those with obesity did not live longer than patients of normal weight. Furthermore, patients with obesity experienced a greater proportion of life spend with cardiovascular disease.

The hazard ratios for CVD incidence for men and women aged 40 to 59 years were 1.21 (95% CI, 1.14-1.28) and 1.32 (95% CI, 1.24-1.40), respectively for overweight (BMI, 25.0-29.9); 1.67 (95% CI, 1.55-1.79) and 1.85 (95% CI, 1.72-1.99) for obesity (BMI, 30.0-39.9); and 3.14 (95% CI, 2.48-3.97) and 2.53 (95% CI, 2.20-2.91) for morbid obesity (BMI, ≥40.0). [2]

Although those with obesity experienced similar longevity to those of normal weight, people who were obese were significantly more likely to develop CVD at an earlier age.

Lead researcher Dr. Sadiya Khan, assistant professor of medicine at Northwestern University Feinberg School of Medicine tells Science Daily: “The obesity paradox caused a lot of confusion and potential damage because we know there are cardiovascular and non-cardiovascular risks associated with obesity.” [2]

This is important research. We are in a midst of an obesity epidemic which will inevitably have dire health consequences for millions of people, including an increased risk of cardiovascular disease, diabetes and some cancers. Obesity also carries a substantial economic cost – according to the Nuffield Trust, obesity cost the NHS an estimated £5.1 billion in 2006/07. [3]

The problem isn’t limited to the UK, the obesity epidemic is a global issue. According to The World Bank, most developing countries are now grappling with the ‘double burden of malnutrition’, that is high levels of obesity alongside rampant undernutrition. [4] And according to the World Health Organisation, in 2016 over 1.9 billion adults were overweight, with over 650 million being obese. [5]

Therefore, research which provides clarification on the risks can only be a positive development – obesity must be reduced, it does not prolong life, it can only increase risk of CVD mortality and morbidity.