Monday, March 30, 2009

Middle Aged? Not Too Late to Get Benefit from Activity

Swedish researchers published in the British Medical Journal (BMJ) a study that aimed to examine how change in level of physical activity after middle age influences mortality and to compare it with the effect of smoking cessation. Researchers surveyed 2205 men aged 50 in 1970-3, then re-examined them at ages 60, 70, 77, and 82 years. They found that mortality was lowest among the most active men. Men who increased their activity level from low/moderate to high between the ages of 50 and 60 saw a drop in mortality after an initial period of 10 years. Before 10 years, no survival advantage was observed. An increase in physical activity has the same impact on lowering mortality rate in the long term as smoking cessation.

Reference Article:

Total mortality after changes in leisure time physical activity in 50 year old men: 35 year follow-up of population based cohort.
Byberg L, Melhus H, Gedeborg R, Sundström J, Ahlbom A, Zethelius B, Berglund LG, Wolk A, Michaëlsson K. BMJ. 2009 Mar 5;338:b688. (Free Full Article)
doi: 10.1136/bmj.b688.
PMID: 19264819

Saturday, March 28, 2009

BMI and mortality

The Body Mass Index (BMI) is one way of assessing weight categories. According to a study published online by the medical journal Lancet, high and Low BMIs were associated with increased mortality risk.

This large research examined data from 57 prospective studies with 894,576 participants, mostly in western Europe and North America. Mortality was lowest among those associated with BMIs in the range of 22.5 to 25 kg/m2. Above 25, every 5-unit increase in BMI translated to a serious 40% higher risk for death from ischemic heart disease or stroke and 10% increased risk for cancer-related deaths.

The authors commented "Although other anthropometric measures (eg, waist circumference, waist-to-hip ratio) could well add extra information to BMI, and BMI to them, BMI is in itself a strong predictor of overall mortality both above and below the apparent optimum of about 22.5—25 kg/m2."

Even though the "normal" BMI range is usually quoted to start from BMI of 18.5, the study showed that adults whose BMI was below 22.5 were also at higher risk for death. However, such a higher mortality was mainly, but not entirely, due to smoking-related lung diseases and cancer.

This important study was funded by UK Medical Research Council, British Heart Foundation, Cancer Research UK, EU BIOMED programme, US National Institute on Aging, and Clinical Trial Service Unit (Oxford, UK).

Reference article:
Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies. Prospective Studies Collaboration. Lancet. 2009 Mar 28;373:1083-1096.
(How to use the doi system?)

Type 2 Diabetes Calculator

There is a nice online type 2 diabetes risk calculator (the QDScore diabetes risk calculator). After you enter the data, see your risk of developing type 2 diabetes. It becomes quite interesting when you start playing with changing your BMI and see what happens to your diabetes risk. Notice that the calculator uses metric system. If you want to calculate your BMI using pounds and feet/inches, you may use the NIH BMI Calculator link. the QDScore diabetes risk calculator is the product of a British research that has recently been published in the British Medical Journal (BMJ).

Using easily collected data (no labs needed) researchers reported that it is possible to determine a patient's 10-year risk for developing type 2 diabetes. To develop the formula (algorithm), the investigators used data on some 2.5 million patients in the U.K. The algorithm was then tested in almost 1.2 million adults. The data needed to be entered for the calculation are simple: age, BMI, family history of diabetes, smoking status, treated hypertension, corticosteroid use, presence of cardiovascular disease, socioeconomic status, and self-reported ethnicity.

Reference article:
Predicting risk of type 2 diabetes in England and Wales: prospective derivation and validation of QDScore. Hippisley-Cox J, Coupland C, Robson J, Sheikh A, Brindle P.
BMJ. 2009 Mar 17;338:b880. (Free Full Article)
doi: 10.1136/bmj.b880.
PMID: 19297312

The QDScore diabetes risk calculator

Friday, March 27, 2009

High Intake of Red and Processed Meats Increases Mortality Risk

A recent research supported by the National Institutes of Health, published in the Archives of Internal Medicine has shown that daily intake of red and processed meats (examples: beef and pork) is associated with increased risk for death in older adults, while white meat (examples: chicken, turkey and fish) may have a small protective effect. This is the largest study ever, including more than a half million adults aged 50 to 71, who were followed for 10 years. After adjustment for BMI and smoking, those who had the highest red meat intake had significantly higher risk of dying overall, and of dying from cancer and cardiovascular disease. Same applied to processed meat (examples: sausage, cold cuts or hot dogs). As the authors pointed out in the discussion of the article, meat is a source of several carcinogens (substances that can cause cancer) which are formed during high-temperature cooking of meat. Iron in red meat may increase oxidative damage increasing the formation of N-nitroso compounds. While red meat is a major source of saturated fat (not good), fish is rich in omega-3 fatty acids (good). In 2004, the FDA Announced a Qualified Health Claim supporting that consumption of omega-3 fatty acids reduces the risk of heart disease (coronary artery disease).

Reference article:

Meat intake and mortality: a prospective study of over half a million people. Sinha R, Cross AJ, Graubard BI, Leitzmann MF, Schatzkin A. Arch Intern Med. 2009 Mar 23;169(6):562-71. [PMID: 19307518] (Free Full Article)

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