March 18, 2009
Biomarkers Show Faster Aging From Obesity, Stress

Telomere caps on chromosomes shorten with age. Obesity and stress are correlated with faster shrinking of telomere caps.

Women who maintain a healthy weight and who have lower perceived stress may be less likely to have chromosome changes associated with aging than obese and stressed women, according to a pilot study that was part of the Sister Study. The long-term Sister Study is looking at the environmental and genetic characteristics of women whose sister had breast cancer to identify factors associated with developing breast cancer. This early pilot used baseline questionnaires and samples provided by participants when they joined the Sister Study.

Two recent papers published in Cancer Epidemiology Biomarkers and Prevention looked at the length of telomeres, or the repeating DNA sequences that cap the ends of a person's chromosomes. Telomere length is one of the many measures being looked at in the Sister Study. Telomeres protect the ends of chromosomes and buffer them against the loss of important genes during cell replication. Over the course of an individual's lifetime, telomeres shorten, gradually becoming so short that they can trigger cell death. The papers show that factors such as obesity and perceived stress may shorten telomeres and accelerate the aging process.

Avoid obesity and stress. Easier said than done of course.

If you get overweight by 40 it is worse than getting overweight later. Probably it is a cumulative effect. The earlier you start the more total cellular damage builds up.

One of the studies published this week found that women who were obese for a long time had reduced telomere length. The researchers looked at the relationship between various measures of current and past body size and telomere length in 647 women enrolled in the Sister Study. They found that women who had an overweight or obese body mass index (BMI) before or during their 30s, and maintained that status since those years, had shorter telomeres than those who became overweight or obese after their 30s. "This suggests that duration of obesity may be more important than weight change per se, although other measures of overweight and obesity were also important," said Sangmi Kim, Ph.D., epidemiologist and lead author on the paper. "Our results support the hypothesis that obesity accelerates the aging process," said Kim.

If you feel stressed and your body has more stress hormones in it then that maximizes the effect of stress on telomere aging.

The other paper published in February looked at the association between telomere length and the perceived stress levels of 647 women enrolled in the Sister Study, and found that similar to the obesity finding, stress can also impact telomere length. The researchers extracted DNA from blood drawn during initial enrollment to estimate telomere length, and measured levels of stress hormones in urine samples the women provided. Additionally, the researchers used a standardized scale to characterize levels of perceived stress based on answers to questions about how stressful participants perceived their life situations. In general, the researchers report that women in the Sister Study typically reported low levels of perceived stress.

"Even so, women who reported above-average stress had somewhat shorter telomeres, but the difference in telomere length was most striking when we looked at the relationship between perceived stress and telomere length among women with the highest levels of stress hormones," said Christine Parks, Ph.D., an NIEHS epidemiologist and lead author on the paper. "Among women with both higher perceived stress and elevated levels of the stress hormone epinephrine, the difference in telomere length was equivalent to or greater than the effects of being obese, smoking or 10 years of aging."

Think about your job decisions, relationship decisions, investment decisions, and spending decisions from the standpoint of which potential decisions carry the risk of creating stress. Avoid putting yourself in situations where you stand a higher chance of feeling stressed. You'll age more slowly and live longer as a result.

Obesity cuts about 3 years off of life expectancy and extreme obesity cuts about 10 years off of life expectancy.

•Above a healthy weight, every 5-point increase in BMI increases the risk of early death by about 30%.

•People who are overweight but not obese, with a BMI between 25 and 29.9, could be shortening their life span by a year.

•People with the lowest risk of dying early are in the high end of the healthy weight range with a BMI of about 22.5 to 25.

Since most people by middle age are overweight a substantial number of people are losing out on some years of life. Here are more details on the study. Go calculate your body mass index (BMI).

Share |      Randall Parker, 2009 March 18 12:11 AM  Aging Weight Studies

HellKaiserRyo said at March 18, 2009 8:06 PM:

I think making people live like hikikomori would reduce the stress of having lower status since they would be isolated from the world.

Bob Badour said at March 19, 2009 5:44 AM:

From what I have seen, what you call a hikikomori, everyone else calls a depressed, lazy youth.

Lou Pagnucco said at March 22, 2009 10:42 AM:

It would be interesting to see if there are differences between long-lived ethnic groups, like Okinawans and Sardinians versus other nearby groups, like Japanese and Italians.

If stress does turn out to reduce telomere length (and telomere length truly drives aging,) we should start seeing some effects on longevity in nations most dramatically impacted by the economic downturn - especially those with no social safety nets.

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