Improvements in Mortality Rates Are Slowed by Rise in Obesity

With countless medical advances and efforts to curb smoking, one might expect that life expectancy in the United States would improve. Yet according to recent studies, there’s been a reduction in the rate of improvement in American mortality during the past three decades. According to a new study published in the Proceedings of the National Academy of Sciences, a rise in obesity is to blame.

The research was performed by Samuel Preston, a sociology professor; Yana Vierboom, a graduate student in demography at Penn; and Andrew Stokes, an assistant professor of global health at Boston University. The team used data from successive cohorts of the National Health and Nutrition Examination Survey from 1988 to 1994 and 1999 to 2010, as well as from the NHANES linked mortality files, which include follow-up into death records through December 2011. The final sample consisted of 25,269 adults aged 40 to 79.

Rather than use a typical measure of obesity, body mass index, or BMI, recorded at baseline, the researchers calculated each person’s lifetime maximum BMI. They found this measure to be more successful at predicting mortality because it is less susceptible to weight loss associated with illness, which biases estimates of the link between BMI and mortality. It also conveys important elements of weight history, which may have enduring effects on health.

“We established a time trend of mortality within this data set,” says Preston, “by dating every observation as it moved forward. We estimated that the impact of rising obesity was about twice as important for mortality trends as the impact of declining smoking. Smoking is such an important variable in mortality analysis, and U.S. mortality is improving faster than it otherwise would because of reductions in smoking, but it’s not improving fast enough to offset the effect of obesity.”

Click here to read the full story.

Arts & Sciences News

Navigating Urban Waters, With an Interdisciplinary Approach

In a research-based fellowship program this summer, a group of Penn graduate and undergraduate students are creating new narratives of their own, tied to water.

View Article >
Cancer Cells Send Out ‘Drones’ to Battle the Immune System From Afar

Researchers show that, to assist in the fight, cancer cells release biological “drones,” small vesicles called exosomes circulating in the blood and armed with the protein PD-L1, which causes T cells to tire before they have a chance to reach the tumor and do battle.

View Article >
Mary Frances Berry Discusses Her New Book “History Teaches Us to Resist: How Progressive Movements Have Succeeded in Challenging Times”

In it, she shares her memories of being a protestor, provides an analysis of protest strategies, and highlights lessons from a lengthy history of fighting against injustice.

View Article >
Greening Vacant Lots Reduces Depression in City Dwellers

Revitalizing dilapidated environments may be an important, inexpensive tool to address mental health in urban communities.

View Article >
Martha Farah Elected to Prestigious British Academy Fellowship

Martha Farah has been made a Fellow of the prestigious British Academy for the humanities and social sciences.

View Article >
A Physics Treasure Hidden in the Pattern of Wallpaper

A newly identified insulating material could one day enable more-efficient electronics or even quantum computing.

View Article >