In the past three decades obesity in the United Kingdom has increased three-fold, emerging as one of the UK’s most prominent public health challenges. Obesity is largely a lifestyle and behavior associated condition, although there are also some genetic factors.
Obesity is measured by a standard anthropometric measurement of known as Body Mass Index (BMI). The terms overweight and obese are usually classified as increased weight-for-height. The figure below classifies the BMI ranges used to define BMI status. (Do you know your BMI?) BMI is calculated by dividing the weight in kilograms by the square of the height in meters. (Or googled)
An individual whose weight is two or more times the ideal weight is classified as morbidly obese.
Recent studies show steady increases in obesity incidence both nationally and internationally. Indeed, today we live in a world where more people are clinically obese than those suffering morbidity or mortality due to starvation.
Globally, the percentage of people classified as overweight or obese increased in both men and women from 28.8% and 29.8% in 1980 to 36.9% and 38.0% respectively. Child overweight and obesity also increased. In 2013, World Health Organization adopted a target of halting the rise in child obesity by 2025.
The primary reason obesity is a public health concern is because it is a risk factor for other non-communicable diseases (NCDs) such as Type II Diabetes Mellitus (T2DM), hypertension and coronary heart disease (CHD). Morbid obesity, considered the most serious stage of obesity, can leave patients at the highest risk of mortality related to their obese status.
Throughout this series I will outline the causes and consequences of rising obesity incidence as identified in empirical studies and literature. All sources are available upon request.
Likely due to methodological challenges, much of the available data on obesity in the UK and elsewhere discuss prevalence and not necessarily incidence. However, understanding disease prevalence and its nuances is useful in interpreting both causal and consequential factors of incidence.
According to Health Survey for England (HSE), in 2013, 26% of men and 24% of women were classified as obese; 41% of men and 33% of women were classified as overweight. Scotland and Wales had similar findings.
The UK has seen increases in obesity in children for several years. In 1995, 11% of boys and 12% of girls were classified as obese. By 2005, these numbers were 18% and 19% respectively. These increases have since leveled off: to 16% of boys and 15% of girls in 2013.
The prevalence of obesity is significantly higher in some groups. Children were more likely to be obese if they lived in an urban area. Whilst 22% of boys and 21% of girls from the lowest-income families were already obese.
Rising incidence of obesity is a problem
The major problem presented is the co-morbidities with which obesity is associated. Obesity is a major risk factor for many NCDs, thus causing and contributing to a high proportion of morbidity and mortality.
Type 2 Diabetes Mellitus (T2DM) is strongly correlated with obesity. The detrimental effects on an individual living with obesity and T2DM are multiple-fold. Rising incidence of obesity in children is well correlated with incidence of childhood T2DM. Expectedly, in terms of reducing the risk of cardiovascular diseases, particularly coronary heart disease, greater reduction in adiposity results in greater risk reduction. With the exception of LDL cholesterol, fat loss in obese patients improves blood pressure, glycemic control and lipids.
T2DM is simply hyperglycemia resulting primarily from a resistance to insulin but also from impaired insulin secretion. Clinical studies have shown the metabolic effects of high sugar, particularly fructose. These sugars mediate fatty liver and insulin resistance in humans. In a typical Western diet, the majority of fructose comes from sugary, soft and fruit drinks, often resulting in significantly elevated levels of fasting glucose and thus, high levels of insulin, leading to resistance.
Obesity also has a role in worsening nocturnal hypoxia in obstructive sleep apnea syndrome (OSAS). It has been theorized that oxidative stress and inflammation caused by OSAS is a major factor causing cardiovascular morbidity and mortality in obese patients.
This series will explore the causes, consequences and some potential solutions to rising obesity incidence in the UK. The significant contribution of behavioural factors to the rising prevalence and incidence of obesity suggests an important role for well-defined interventions to manage and reduce obesity levels. It is clear, however, that the burden and cost of the consequences of obesity justify the need for the United Kingdom to aspire to meet its own targets and those set by the World Health Assembly.