Academic Research on Longevity and Its Link to Gender, Race, and Education

Gender

Women live longer than men. By how much? And why? Here's the most prominent research on why that's the case, how big the gap is, and what we can expect to happen in the future.

In nearly every corner of the world, women outlive men on average. Naturally, scientists and physicians have long been searching for an answer to the persistent gap in longevity between the genders. Hardly shocking, the answer is complex, and not a definite one.

In a Harvard Medical School study, researchers suggest that the gap is a result of behavioral and biological differences between the genders, as well as social and psychological factors, and medical advances. Medical advances in obstetrical care during the 1900s made for large gains in female longevity. On the other hand, increased availability of cars and guns have led to increases in male mortality among certain cohorts. Harvard Medical School researchers, Thomas Perls and Ruth Fretts, suspect that higher testosterone levels in males fuel more reckless behavior, “because the male hormone has been linked with aggression and competitiveness as well as libido.” In adolescence, this manifests largely in premature death from vehicle accidents, and middle age men are still twice as likely as women to be in a fatal car accident, and four times as likely to take their own life. Furthermore, in a study by Martin Daly and Margo Wilson, evolutionary psychologists, 35 homicide data sets from 14 countries were examined, concluding that men are 26 times more likely than women to commit homicide, and are the victims of homicide 70% of the time.

The impact of “toxic testosterone,” as some researchers have started calling it, goes beyond behavioral effects. In addition to behavioral effects, testosterone increases LDL, known as the “bad cholesterol.” Therefore, males tend to have greater incidence of fatal conditions, such as heart disease and certain types of cancers, whereas women tend to develop nonfatal, chronic conditions, such as osteoporosis and arthritis. However, according Kathy Gyngell of the Centre for Policy Studies this distinction may be fading. As she puts it:

The narrowing of the life expectancy gap is indicative of the process of women moving into roles that were once taken by men. We are increasingly seeing more women suffering from what were once male diseases - heart disease, high blood pressure, even baldness. Women deal with the pressure of work, and many have to juggle part-time work and childcare.

The increased risk of these diseases has taken a toll on female longevity, and men moving away from dangerous roles of manual labor, are contributing to the narrowing gap between male and female life spans. While both male and female lifespans are increasing, that of males is increasing at a greater rate. A study by the Office of National Statistics in the United Kingdom points to medical advances in circulatory illnesses, a predominantly male disease, and changes in smoking habits, a vice traditionally more popular in males, but with increasing popularity among young females.

Whatever the reason, the gap is undoubtedly narrowing while both genders' lifespans increase. According to the Center for Disease Control and Prevention, the female lifespan is about 80 years, and that of males is about 75 years, a mere five year gap. Researchers believe that the gap will continue to shrink, with both genders' increasing their longevity, but males at a slightly higher rate.

As it stands right now around the world, women, on average, live longer than men. It's an irrefutable fact. But what's also undeniable is the fact that men are catching up, closing the life expectancy gap that has long existed. The cause of this gap is complicated, and not entirely understood. There are biological theories, focusing on the gender differences in disease development, with males developing more fatal conditions, and women more chronic, nonfatal ones, as well as behavioral theories, pointing to the impact of testosterone in relation to fatal accidents and aggressive behavior in males. And just as the root of the gap isn't entirely clear, the reason for its recent narrowing is a grey area, with changing social roles, medical advances, and perhaps women reaching the ceiling of the human lifespan. Likely, the source of the gap and its closing is a combination of factors. Whatever the reason, though, science says that both males and females will continue making gains in longevity in the coming years.

Other Determinants of Longevity

How race, marital status and education impact longevity. Research has shown certain races live longer on average. Marital status and education also hold some explanatory power in most statistical models, including ours. Read on for a summary of the research.

Data from the Center for Disease Control and Prevention divides the U.S. population into five racial groups, providing the average life expectancy for each group. Asian-Americans top the list at 86.5 years, with Latinos following closely behind at 82.8 years. Third of the five groups are Caucasians, with an average life expectancy of about 78.9 years, followed by Native Americans at 76.9 years. The final group, African Americans, has a life expectancy of 74.6 years. In our model, the same relationship generally holds, although we see similar life expectancies between Asian-Americans and Hispanics and not quite as large a discrepancy between different races. That said, there's no question about the gap in longevity amongst the races. The real question is why the gap exists.

Current research focuses on the discrepancy between Caucasians and African Americans. Both African American males and females have a shorter life expectancy than their Caucasian counterparts, by 5 years and 3.3 years, respectively. A data brief by the National Center of Health Statistics suggests that this difference is caused by higher incidence of a number of conditions among African Americans, including 8 of the 15 leading causes of death, according to a report by the National Vital Statistics Report. Specifically, in males, these conditions include heart disease (the leading cause of death in the U.S.), cancer, stroke, and perinatal conditions. In addition to greater incidence of medical complications, African American males are at greater risk of death via homicide. African American females also suffer from higher risk of heart disease, cancer, stroke, and perinatal conditions. But they also have the added complication of a higher risk of diabetes, relative to Caucasian females. Research suggests, however, that this gap between the two races is narrowing, from just about 8 years in 1970 to about 4 years today. Research has attributed this narrowing gap to lower rates of chronic lower respiratory disease, Alzheimer's, chronic liver disease, unintentional injuries, and suicide in African Americans.

Apart from race, science has found that marital status and longevity are historically related, though the relationship may be weakening over time. A study published in the Journal of Epidemiology & Community Health tells us that, undoubtedly, those who are currently married have the longest life expectancy, and never having married was the strongest predictor of premature mortality, relative to other relationship classifications. This “never married effect” has a significantly stronger effect on men than women. Similar to the gap between races, the question is not about the existence of a gap, but the reasoning.

In summary, it is not the marriage itself that promotes longevity, but rather the people who tend to wed and the demands and behaviors associated with marriage. For this reason, and due to changing societal relationship norms, the gap between married and never married people is shrinking, says a National Health Interview Study. In recent years, long-term, spouse-like relationships have become socially acceptable and common, a big change from the past. These relationships are qualitatively quite similar to a marriage, with these couples often buying a home together, sharing finances and possessions, and raising children together. Therefore, though these people technically fall under the “never married” status, they are far more similar to those in the “currently married” category, in both the types of people they are and the lives they lead.

The science is clear: longevity is a multidimensional phenomenon with some variables under one's control, and others a matter of chance. The variables of chance, here being race, emphasize the importance in doing everything we can to further our lifespan through healthy dietary habits, exercise regimes, and lifestyle choices.