Older People Live Longer with a Few Extra Pounds,
Gaining Late in Life May Be Deadly
Change in weight in older years more important than
where you start - about 7.2% of deaths after age 51 due to weight gain
among obese people
Sept. 19, 2013 - Some overweight older adults don’t
need to lose weight to extend their lives, but they could risk an
earlier death if they pack on more pounds. A multi-year study of adults,
age 51 to 61 at the start, has found slightly overweight people (BMI of
25 to 29.9) whose weight was steady had the highest survival rate, those
who moved from overweight to obese (BMI 30 to 34.9) were close behind.
Those most likely to die started out as very obese in their 50s and
continued to pack on pounds.
In fact, the nationwide study found that people who
were slightly overweight in their 50s but kept their weight relatively
stable were the most likely to survive over the next 16 years.
They had better survival rates than even
normal-weight individuals whose weight increased slightly, but stayed
within the normal range.
On the other hand, those who started out as very
obese in their 50s and whose weight continued to increase were the most
likely to die during that period.
Overall, the results suggest that about 7.2 percent
of deaths after the age of 51 are due to weight gain among obese people,
at least among the generation in this study, said
Hui Zheng, lead author of the study
and assistant professor of
sociology at The Ohio State University.
“You can learn more about older people’s mortality
risk by looking at how their weight is changing than you can by just
looking at how much they weigh at any one time,” Zheng said.
While some extra weight seemed protective in this
study, Zheng cautioned that these results applied only to people over
previous research, published in Social Science & Medicine,
suggests that being overweight may not be helpful for younger people.
“Our other research suggests that the negative
effect of obesity on health is greater for young people than it is for
older people, so young people especially shouldn’t think that being
overweight is harmless,” he said.
The researchers used data from the
Health and Retirement Study, a
nationally representative survey of Americans born between 1931 and
1941. This study analyzed 9,538 respondents who were aged 51 to 61 when
the survey began in 1992. They were re-interviewed every two years until
2008, and the researchers had information on how their
body mass index (BMI) changed at
each interview and whether they died at any point before December 2009.
Body mass index measures weight relative to height
and is often used to evaluate obesity.
Zheng and his colleagues classified respondents
into six groups, depending on their BMI at the beginning of the study
and how it changed over the 16-year period they were surveyed.
While slightly overweight people (BMI of 25 to
29.9) whose weight was steady had the highest survival rate, those who
moved from overweight to obese (BMI 30 to 34.9) were close behind.
“This suggests that among overweight people at age
51, small weight gains do not significantly lower the probability of
survival,” Zheng said.
The third highest survival rate among the six
groups was normal weight individuals (BMI of 18.5 to 24.9) whose weight
increased slightly, but stayed within normal range.
Next came the Class I obese (BMI of 30 to 34.9)
whose weight was moving upward.
“You can learn more about older people’s
mortality risk by looking at how their weight is changing than
you can by just looking at how much they weigh at any one time.”
Next to last were normal weight individuals who
lost weight. Although the study attempted to control for illnesses
among those studied, it may be that many of these individuals dropped
weight because of illness.
The most obese individuals (BMI of 35 and over) who
continued to add weight had the lowest survival rate of the six groups.
There weren’t enough people who started out as
overweight and obese and lost weight to include in this analysis, Zheng
“We can’t really evaluate the effectiveness of
planned weight loss on mortality. Even in the normal-weight people in
this study, there was no way to tell whether weight loss was planned,”
Zheng noted that the study took into account a wide
variety of demographic and socioeconomic factors that may play a role in
both weight and mortality among Americans. The researchers also
controlled for whether the respondents smoked, whether they had a
variety of chronic illnesses and even how they rated their own health.
The results stood even after all of these factors were taken into
Why is being slightly overweight protective for
“It is probably because the older population is
more likely to get illnesses and disease, especially cancer, that cause
dangerous weight loss,” he said. “In that case, a small amount of extra
weight may provide protection against nutritional and energy
deficiencies, metabolic stresses, the development of wasting and
frailty, and loss of muscle and bone density caused by chronic
Younger people are less likely to get many of the
diseases that afflict older adults, which is one reason extra weight is
not good for them, he said.
But Zheng said the main message for everyone,
including older adults, is that packing on the pounds, especially if
you’re obese, can be hazardous to your health.
“Continuing to put on weight can lower your life
expectancy,” he said.