Risk factors

There are many risk factors driving the global epidemic of chronic disease, including aging populations, genetic factors, alcohol overuse and – the three major risk factors – tobacco use, poor diet and lack of physical activity.

Many of the risk factors are themselves influenced by socioeconomic determinants, which restrict the lifestyle choices available to individuals. For example, poverty restricts the food choices available, often curtails access to health care (such as drugs to control blood pressure), and individuals are more likely to be under chronic stress. In addition, the socioeconomically disadvantaged are often the least well-educated, and may not be aware of the health consequences of the lifestyle choices over which they have control.

Tobacco use

There are an estimated 1.3 billion smokers today, 84 per cent of whom live in developing/transition economies, and half of whom will be killed by their habit. Second-hand smoking increases the chances of lung cancer by 20–30 per cent and heart disease by 25 per cent. In 2005, tobacco was responsible for 5 million deaths – this is set to double by 2020.

Poor diet

Most parts of the world are undergoing a ‘nutrition transition’, as sugars and fats have become cheaper relative to healthier and more traditional foods – making them more accessible to those on lower incomes. 1.6 billion people are now overweight or obese in the world – more than are underweight. Overall, 2.7 million deaths each year worldwide are attributable to low fruit and vegetable intake.

Lack of physical activity

30 minutes of moderate physical activity for adults, five days per week (one hour every day for children) is regarded as adequate by the WHO, but for many it is increasingly difficult to build physical activity into everyday life. Urbanisation means that jobs often involve less physical activity and streets may not be safe places to walk and play; labour-saving devices in the home are increasingly affordable; motorised transport is more freely available. Overall, 1.9 million deaths each year worldwide are attributable to physical inactivity.