Smoking is a leading cause of multiple diseases, including cancers, heart attacks and stroke, and respiratory diseases such as chronic obstructive pulmonary disease. Smoking among pregnant woman increases the risk of low birth weight and premature delivery. The WHO estimates that tobacco smoking kills 7 million people in the world every year, of which more than 1.2 million deaths are due to second-hand smoke and 65 000 are children (WHO, 2017[1]). Of these deaths, just over half took place in four countries – China, India, the United States, and the Russian Federation. Over recent decades, smoking caused the largest share of overall years of healthy life lost in 15 OECD countries, and ranked second in further 16 OECD countries (Forouzanfar et al., 2016[2])

Alcohol use is a leading cause of death and disability worldwide, particularly in those of working age. It accounted for an estimated 7% of male and 2% of female deaths worldwide in 2016 (Griswold et al., 2018[1]). High alcohol intake is a major risk factor for heart diseases and stroke, liver cirrhosis and certain cancers, but even low and moderate alcohol consumption increases the long-term risk of these diseases. Alcohol also contributes to more accidents and injuries, violence, homicide, suicide and mental health disorders than any other psychoactive substance, particularly among young people.

Opioids are a narcotic pain medication that have become the cornerstone therapy for treatment of moderate to severe pain in many high-income countries. In parallel, illicit opioid use for nonmedical purposes has created illegal, increasingly commercialised global markets. Canada and the United States have experienced an opioid crisis in recent years, fuelled by growth in the consumption of synthetic opioids such as fentanyl and carfentanil. Problematic opioid use is also spreading in Australia and some European countries, due to growing prescription rates (see indicator on “Safe primary care – prescribing” in Chapter 6) and the development of a dynamic illegal drug supply market (OECD, 2019[1]).

A healthy diet is associated with improved health outcomes. Adults who follow a diet rich in fruits and vegetables and low in fat, sugars and salt/sodium are at a lesser risk of developing one or more cardiovascular diseases and certain types of cancer (Graf and Cecchini, 2017[1]). Healthy diet may also reduce the likelihood of being overweight or obese. In 2017, inadequate fruit and vegetable consumption led to an estimated 3.9 million deaths worldwide (Global Burden of Disease Collaborative Network, 2018[2]).

Being overweight, including pre-obesity and obesity, is a major risk factor for various non-communicable diseases including diabetes, cardiovascular diseases and certain cancers. High consumption of calories-dense food and increasingly sedentary lifestyles have contributed to growing global obesity rates. The rate of growth has been highest in early adulthood and has affected all population groups, in particular women and those with lower levels of education (Afshin et al., 2017[1]). High body mass index (BMI) has been estimated to cause 4.7 million deaths worldwide (Global Burden of Disease Collaborative Network, 2018[2])

Childhood overweight rates, including pre-obesity and obesity, have been growing worldwide. Environmental factors, lifestyle preferences, genetic makeup and culture all can cause children to be overweight. Obese children are at greater risk of developing hypertension and metabolic disorders. Psychologically, obesity can lead to poor self-esteem, eating disorders and depression. Further, obesity may act as a barrier for participating in educational and recreational activities. Childhood obesity is particularly concerning as it is a strong predictor of obesity in adulthood, which is linked to diabetes, heart disease and certain types of cancer (Bösch et al., 2018[1]; OECD, 2019[2]).

Climate change is one of the biggest challenges of present and future generations. It is linked to different types of environment distress, including air pollution and extreme temperatures. Air pollution is already a major cause of death and disability today, and its future impact is likely to be even greater without adequate policy action. Projections have estimated that outdoor air pollution may cause 6 to 9 million premature deaths a year worldwide by 2060, and cost 1% of global GDP as a result of sick days, medical bills and reduced agricultural output (OECD, 2015[1]).