Global Inequalities in Human Mortality

Human mortality is not evenly distributed across global populations, with the timing, causes, and circumstances of death varying significantly based on socioeconomic dimensions. While global deaths are expected to reach approximately 64 million individuals in 2026, a profound gap remains between privileged and marginalized groups, often resulting in premature death in low-income regions due to poverty, conflict, and limited healthcare access.

According to a global report from the World Health Organization (WHO), these health inequities can shorten lives by decades. On average, individuals born in the country with the lowest life expectancy live 33 years shorter than those born in the country with the highest life expectancy.

Regional Disparities in Life Expectancy and Infant Mortality

Significant disparities in death rates are evident in life expectancies at birth. Some sub-Saharan African countries, including Nigeria, Chad, and South Sudan, report some of the lowest life expectancies, at approximately 55 years.

These disparities are particularly acute during the first year of life. Countries such as Finland, Japan, and Iceland maintain some of the lowest infant mortality rates, with fewer than 2 infant deaths per 1,000 live births. In contrast, nations including Nigeria, Somalia, and Niger experience rates exceeding 62 infant deaths per 1,000 births, a figure more than 30 times higher than the lowest recorded rates.

Maternal mortality reflects similar geographic inequalities. In 2023, maternal mortality rates in sub-Saharan African nations such as Chad, Nigeria, and South Sudan exceeded 1,000 deaths per 100,000 births.

Shifting Causes of Global Mortality Inequality

Research analyzing data from the Global Burden of Disease Study 2021 (GBD 2021) indicates that while cross-country socioeconomic inequalities in all-cause age-standardized mortality (SIAM) persist, the underlying causes are shifting. Between 1990 and 2021, the contribution of nutritional, neonatal, maternal, and communicable diseases to SIAM fell from 81.2% to 56.6%.

During the same period, the contribution of non-communicable diseases rose from 13.2% to 27.8%. By 2021, the five leading causes of death contributing to SIAM were:

• COVID-19 (17.9%)
• Stroke (9.4%)
• Tuberculosis (7.3%)
• Lower respiratory infections (7.0%)
• Diarrheal diseases (5.5%)

The study also identified the top five risk factors contributing to these inequalities in 2021. Household air pollution resulting from solid fuels was the primary driver at 17.2%, followed by high systolic blood pressure (9.9%), unsafe sex (4.6%), high fasting plasma glucose (4.4%), and unsafe water sources (4.2%).

Social Determinants and Systemic Inequity

The WHO emphasizes that the drivers of ill health often exist outside the healthcare sector. Social determinants—including job opportunities, education, and the quality of housing—can influence health outcomes more significantly than genetic factors or direct access to medical care.

Health typically follows a social gradient where populations in more deprived areas face lower incomes and fewer years of education, which correlates with poorer health and fewer healthy years of life. These inequities are further intensified for populations facing marginalization, and discrimination.

Indigenous Peoples, for example, have lower life expectancies than non-Indigenous Peoples across both high-income and low-income countries. Higher maternal mortality rates are strongly associated with higher levels of gender inequality, including the practice of child marriage.

Our world is an unequal one. Where we are born, grow, live, work and age significantly influences our health and well-being

Dr Tedros Adhanom Ghebreyesus, WHO Director-General

To overcome these deep-seated inequities, the WHO advocates for measures that address structural discrimination, income inequality, climate disruptions, and conflict.