Junkfood Science: Truth comes hard

July 07, 2007

Truth comes hard

How to explain away findings that don’t support the “obesity crisis” is an ongoing challenge for researchers. One of the more popular beliefs that continues to this day, despite having been disproven more than half a century ago, is that obesity causes heart disease and high blood pressure. This months’ journal Epidemiology published a 15-year study finding that as BMI (body mass indexes) significantly rose, the prevalence of hypertension decreased. So, how was it reported?

Obesity link to high blood pressure has weakened

The Reuters Health article said:

It seems that the association between body mass index (BMI) and high blood pressure or hypertension has decreased since 1989, researchers say. The finding suggests that obesity may not have as much of an impact on heart-related disease as previously thought....

There was a slight decrease in average blood pressure between 1989 and 2004 in both men and women. The prevalence of high blood pressure changed little during this time -- from 45 to 44 percent in men and from 34 to 36 percent in women. The percentage of people who were overweight, defined as a BMI of 25 or more, increased from 39 percent to 60 percent between 1989 and 2004.

However, the association between BMI and BP decreased “substantially and consistently" between 1989 and 2004, irrespective of sex, Bovet's team writes. “If confirmed, a decreasing association between BMI and blood pressure over time could imply that the impact of the overweight epidemic on cardiovascular disease might be less important than predicted," the investigators conclude.

The little known fact was placed at the end of the article, where the researchers acknowledged that their study actually confirms the real life evidence, saying: “This decreased relationship could also help to explain the current favorable trends in cardiovascular disease (declining incidence) observed in many countries despite the increasing prevalence of obesity.”

This study was led by researchers from the Institute of Social and Preventive Medicine, University of Lausanne, Switzerland. They examined representative population examination surveys conducted on more than one thousand adults in the Seychelles in 1989 and 2004.

The Seychelles is a small country of several islands in the Indian Ocean, off the coast of Kenya, with a population of approximately 80,300. According to the Country Studies of the U.S. Department of the Army, it’s an ethnically diverse population (African 65%, European (Caucasian) 10%, Asian 5% and mixed 20%) and enjoys health and nutrition similar to developed countries. Since the 1970s, it has had rapid economic growth due to a thriving tourist industry.

The researchers found little change in age-standardized prevalence of hypertension, with a slight decrease of 1% - 2% over the past fifteen years. In contrast, the prevalence of those with BMIs of 25 or greater had increased by 21% (going from 39% to 60%). Of specific note, is that the inverse correlation between BMI and high blood pressure was unrelated to anti-hypertensive treatment and was seen among all sizes and ages.

This concurs with other research, such as clinical studies on mature women conducted by Dr. László B. Tankó, M.D., Ph.D. and colleagues in Denmark. In a 2003 issue of Circulation and 2005 issue of Archives of Internal Medicine, they reported that natural body fat on women actually had a dominant anti-atherogenic benefit. “The lowest aortic calcification scores [and other metabolic risk factors] were found in women with a high percentage of central body fat (21.6±0.1%) and high percentage of peripheral fat (27.3±0.14%).” They said their studies demonstrated that “generally obese women enjoy cardiovascular benefits of their excessive peripheral fat mass,” possibly due “to the excessive secretion of adiponectin from subcutaneous adipocytes, which provides insulin-sensitizing, anti-inflammatory, and antiatherogenic effects.”

The admission of the researchers in this latest study bears repeating as it certainly has not been plastered all over the news: favorable trends in cardiovascular disease (declining incidence) have been observed in many countries, despite the increasing prevalence of obesity.

© 2007 Sandy Szwarc

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