Which factor has the largest effect on life expectancy?

• A. Genetics
• B. Access to healthcare
• C. Socio-economic status
• D. Lifestyle choices

Answer: (C)

The main idea here is how the broader environment in which people live shapes how long they live. Socio-economic status has the largest effect on life expectancy because it governs access to resources, opportunities, and protections that influence health across the lifespan. Higher SES generally means safer neighborhoods, better housing, cleaner environments, more stable employment, greater educational opportunities, and easier access to nutritious foods and preventive healthcare. These advantages reduce exposure to health risks and increase the likelihood of early detection and treatment for illnesses, contributing to longer lifespans. Lower SES, on the other hand, often comes with financial stress, housing instability, food insecurity, limited health literacy, and barriers to care, which accumulate to elevate risk for chronic diseases and premature death. Genetics set baseline susceptibility for some conditions, but population-level differences in life expectancy are explained far more by social and economic conditions. Lifestyle choices matter, yet many health behaviors are shaped by the options and stressors present in one’s environment and resources, so their impact is intertwined with SES. Access to healthcare is essential, but the capacity to benefit from it is deeply influenced by socio-economic context.