Life expectancy across the world is expected to increase by almost five years by 2050, new findings suggest.

The forecast indicates that between 2022 and 2050 the life expectancy for men is expected to increase from 71.1 years to 76 years, and from 76.2 years to 80.5 years for women.

According to the Global Burden of Disease Study (GBD) 2021, countries where life expectancy is currently lower are expected to see the largest increases.

The trend is largely driven by public health measures that have prevented, and improved survival rates from, cardiovascular diseases, Covid-19, and a range of communicable (diseases that spread from one person to another), maternal, neonatal, and nutritional diseases (CMNNs), the experts say.

Dr Chris Murray, chairman of health metrics sciences at the University of Washington in the US, and director of the Institute for Health Metrics and Evaluation (IHME), said: “In addition to an increase in life expectancy overall, we have found that the disparity in life expectancy across geographies will lessen.

“This is an indicator that while health inequalities between the highest and lowest income regions will remain, the gaps are shrinking, with the biggest increases anticipated in sub-Saharan Africa.”

Although global life expectancy is forecast to increase from 2022 to 2050, the improvement was at a slower pace than in the three decades preceding the Covid-19 pandemic, the study found.

This study indicates that the ongoing shift from non-communicable diseases (NCDs) – like cardiovascular diseases, cancer, and diabetes – and exposure to NCD-associated risk factors – such as obesity, high blood pressure, unhealthy diet, and smoking – will have the greatest effect on the impact of health issues of the next generation.

Global life expectancy is forecast to increase from 73.6 years of age in 2022 to around 78.1 years of age in 2050 (a 4.5-year increase).

But global healthy life expectancy – the average number of years a person can expect to live in good health – will increase from 64.8 years in 2022 to 67.4 years in 2050 – an increase of only 2.6 years.

This suggests that while more people are expected to live longer, they are expected to spend more years in poor health.

The findings build upon the results of the GBD 2021 risk factors study, also released on Thursday in The Lancet.

The research found that the total number of years lost due to poor health and early death attributable to metabolic risk factors, such as high blood pressure, high blood sugar, and high BMI, has increased by almost 50% (49.4%) since 2000.

The analysis based its estimates on 88 risk factors and their associated health outcomes for 204 countries and territories from 1990 to 2021.

Particulate matter air pollution, smoking, and low birthweight and short gestation were also among the largest contributors to lost years of healthy life due to poor health and early death in 2021, with considerable variation across ages, sexes, and locations.

The study found that substantial progress was made between 2000 and 2021 in reducing disease attributable to risk factors linked to maternal and child health, unsafe water, sanitation, and handwashing; and household air pollution from cooking with solid fuels.

Dr Emmanuela Gakidou, professor of health metrics sciences at the IHME, said: “Risk factors that currently lead to ill health, such as obesity and other components of metabolic syndrome, exposure to ambient particulate matter air pollution, and tobacco use, must be addressed via a combination of global health policy efforts and exposure reduction to mitigate health risks and improve population health.”

Dr Murray said: “There is immense opportunity ahead for us to influence the future of global health by getting ahead of these rising metabolic and dietary risk factors, particularly those related to behavioural and lifestyle factors like high blood sugar, high body mass index, and high blood pressure.”