People who have more money generally live longer lives. But the reverse is also true—those with less money tend to live shorter lives. Unfortunately, this income-mortality disparity has broadened in recent years. For instance, men born in 1930 who are in the highest quartile of earning live an average of 5.1 years longer than men in the lowest quartile of earning—a difference that’s projected to increase to 12.7 years for men born in 1960, according to research published by the National Academies of Sciences, Engineering, and Medicine. This gap is even more pronounced in women, with a projected increase in the difference between low- and high-income earners expected to jump from 3.9 years for the 1930 birth cohort to 13.6 years for the 1960 birth cohort. A plethora of data have linked lower socioeconomic status to morbidity and mortality. But how does poverty directly contribute to worse health? Stress and environmental factors The stress of poverty could exert the biggest impact on health status. Extreme stress experienced at home and work can interfere with digestion and reproduction. It can also cause blood pressure levels to increase. Over time, this stress can lead to illness and poor health status. In addition, financially disadvantaged children are often exposed to more toxins, violence, and noise. These environmental factors can also adversely affect brain development and cause the body to release cortisol, which activates the sympathetic nervous system and places the body in fight-or-flight status. Cortisol also increases heart rate. In a study published in the Undergraduate Journal of Mathematical Modeling: One + Two, heart rate was more highly correlated with longevity than either blood pressure or obesity. (On a related note, people who want to live longer should increase their amounts of aerobic exercise, at least according to this study.) Epigenetic changes An emerging line of research suggests that poverty can result in epigenetic changes, or a change in how genes are expressed. Surprisingly, these epigenetic changes can begin even in the fetus. In one study, researchers found evidence that poverty can become embedded across wide swaths of the genome. They discovered that lower socioeconomic status is associated with levels of DNA methylation—an epigenetic mark that can shape gene expression—at more than 2,500 sites across more than 1,500 genes. Put another way, poverty leaves a mark on nearly 10% of the genes in the genome. Impoverished neighborhoods Sure, diet and exercise are important facets of health. But researchers have shown that these health factors are rooted in where a person lives. Impoverished neighborhoods often lack access to nutritious foods and good schools, and tend to be infested with crime. In some places, simply jogging down the street can be hazardous to your health. On the upside, strategies to improve lower socioeconomic neighborhoods can also improve the health of the people living there, according to a study by researchers at the University of California San Francisco (UCSF), San Francisco, CA. “When these children from lower economic-status families were living in more resourced neighborhoods that are quality neighborhoods—those with greater access and supportive services—they had those lower levels of cortisol and fewer health problems than the lower socioeconomic children living in poor-quality neighborhoods,” said first author Danielle Roubinov, PhD, assistant professor of psychiatry, UCSF. Access Lack of health insurance is a huge problem in the United States. To receive proper treatment for complex diseases, people need access to specialist care. To boot, people need time to see their primary care physicians or specialists. However, those of lower socioeconomic status often have jobs that don’t allow much flexibility to take the necessary time off. Limited access to proper healthcare can even be more insidious. For instance, a mother living in a shelter may lack access to refrigeration needed for her child’s prescription antibiotics. Despite politicians decrying the much-contested Affordable Care Act, analysts have shown that it has substantially improved health insurance coverage and access to healthcare for people of lower socioeconomic status, and has significantly reduced socioeconomic gaps in healthcare access. Education In a study published in Nature Neuroscience, investigators looked at the relationship between socioeconomic factors and brain morphometry while controlling for genotype. In 1,099 participants aged 3-20 years, income was related to brain surface area. Keep in mind that surface area increases with cortical folding. In children from lower-income families, even small differences in income were related to big differences in brain surface area. In children from higher-income households, similar small changes were correlated with small differences in surface area. Importantly, the researchers found that women who received more education had children with higher brain surface area. Increased surface area was seen in regions of the brain responsible for reading, language, executive function, and special skills. Increased surface area also led to improved neurocognitive capability. “These differences are the central nervous system underpinnings of growing up in poverty,” said Tom Boyce, MD, chief, Division of Developmental Medicine, University of California San Francisco, who was not involved in the study. “It is especially important to understand that finding neurobiological differences among children from disadvantaged communities does not imply that the differences are genetic in origin,” Dr. Boyce added. “Rather, many or even most such socioeconomic disparities in brain structure and function are the direct consequences of early rearing in impoverished, chaotic and stressful conditions.” Source
