20th February 2024

Obesity and its impact

Epidemiology

The incidence of obesity is rising worldwide, with up to 1 in 4 adults in the UK classified as obese. This appears to be worse in the lower socioeconomic populations and those of African, Caribbean and Pakistani descent. Modifiable obesity-related factors include food consumption, physical activity and psychological factors. Other non-modifiable factors include genetics, associated medical conditions and medication use. 

The body mass index (BMI) identifies and quantifies obesity. The cut-off utilised by NICE is as follows:

• Healthy – 18.5-24.9kg/m²
• Overweight – 25-29.9 kg/m²
• Obesity I – 30 – 34.9 kg/m²
• Obesity II – 35-39.9 kg/m²
• Obesity III – ≥ 40 kg/m²

In addition, waist circumference is also utilised in patients with BMI<35kg/m2 to identify obesity-related problems. A waist circumference of ≥ 94cm in males and ≥ 80cm in females indicates an increased risk for obesity-related problems. 

Obesity is caused by a mismatch between energy intake and expenditure, with its direct pathophysiology not wholly known. Hormones like leptin and ghrelin have been shown to affect the central nervous system regarding appetite. 

Impact on health

Obesity is one of the leading causes of death worldwide. It is associated with an increased risk of chronic conditions, including ischaemic heart disease, type 2 diabetes mellitus, metabolic syndrome, oesophageal reflux, cancer, obstructive sleep apnoea and osteoarthritis. 

It also results in a direct reduction in life expectancy with increased costs associated with healthcare visits. 

References

• Frantzides, C. T., & Luu, M. B. (2020 Jan 28). Obesity in Adults. Accessed on 2022 Mar 26. Available from: https://bestpractice.bmj.com/topics/en-gb/211. 
• National Institute for Health and Care Excellence. (2014). Obesity: identification, assessment and management. Accessed on 2022 Mar 26. Available from: https://www.nice.org.uk/guidance/cg189/resources/obesity-identification-assessment-and-management-pdf-35109821097925. 
• National Institute for Health and Care Excellence Clinical Knowledge Summary. (2017). Obesity. Accessed on 2022 Mar 26. Available from: https://cks.nice.org.uk/topics/obesity/. 
• Perreault, L., & Apovian, C. (2021 Jul 12). Obesity in adults: Overview of management. Accessed on 2022 Mar 26. Available from: https://www.uptodate.com/contents/obesity-in-adults-overview-of-management?search=obesity&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1.