Commentary by Cara Litvin MD, Executive Editor, Clinical Correlations
First let’s start off with some rare good news in the political arena. Last week, the Senate overwhelmingly voted to override President Bush’s veto on a controversial Medicare bill that reverses a scheduled 10.6% cut in Medicare payments to doctors. Senator Edward Kennedy even made a dramatic appearance to cast his vote. The bill also reduces federal payments to private Medicare Advantage plans. The government currently subsidizes Medicare Advantage plans, paying on average 13% more for the same services than the traditional Medicare program, thereby generating larger profits for these private companies.
Tomatoes are now safe!! After weeks of investigation, the FDA announced last week that fresh tomatoes are no longer thought to be involved in the recent outbreak of Salmonella Saintpaul, revoking its previous warning against eating certain types of raw tomatoes. The prior warning had hit the tomato industry hard, even causing McDonald’s to temporarily remove tomatoes from its menu. The villains are now believed to be raw jalapeno peppers.
Despite recently avoiding tomatoes, we’re all still getting plenty to eat. The CDC recently announced the results of a 2007 survey, estimating that 25.6% of the nation is obese (as defined by a BMI greater than or equal to 30), compared to 23.9% in 2005. More notably, in 1995, the prevalence of obesity was only 15.3%. The South leads the nation in obesity, with nearly a third of all adults considered obese in several Southern states. Despite a goal set by the national health promotion program Healthy People 2010 of a prevalence of obesity of 15% by 2010, no state currently meets this goal.
So what’s the best way to lose weight? A study in the NEJM last week compared the effectiveness of three weight-loss diets. Moderately obese participants were assigned to one of three diets, including a low fat/calorie restricted diet, a Mediterranean/calorie restricted diet, or a low carb/calorie non-restricted diet. The participants were followed for 2 years, with a mean weight loss of 2.9 kg for the low fat group, 4.4 kg for the Mediterranean group, and 4.7 kg for the low carb group. While there were no significant changes in LDL amongst the groups, HDL increased in all groups, with the greatest increase in the low carb group. Levels of the biomarker CRP also decreased significantly in the Mediterranean and low carb group. Thus both the Mediterranean and the calorie non-restricted diets appear to be safe, effective and appealing to many people who have a hard time adhering to a low fat diet or calorie restricted diet.
Speaking of biomarkers, published in the Lancet this week was a study suggesting that the ratio of two lipoproteins is a better predictor of myocardial infarction than any cholesterol measurement. In the case control study which involved over 27000 subjects, the ratio of apolipoprotein B/apolipoprotein A1 had a PAR (population-attributable risk) for myocardial infarction of 54%, while the PAR for LDL/HDL was 37% and the PAR for total cholesterol/HDL was 32%. Odds ratios for myocardial infarction were also highest for the ApoB/ApoA1 measurement, which does not require fasting prior to testing. The authors of the study propose that apolipoprotein measurement be widely introduced into clinical practice and even suggest that apolipoprotein measurement be a final test of any LDL cholesterol lowering treatment, although more studies are obviously needed to determine how such practice would affect clinical outcomes.