Research Collected: August and September 2014

low-carb and low-fat diets, obesity,  genetics, cancer screening in older populations, Alzheimer’s, Tylenol, cannabis

Effects of Low-Carbohydrate and Low-Fat Diets: A Randomized Trial, 2014

“Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight…, fat mass…, ratio of total–high-density lipoprotein (HDL) cholesterol…, and triglyceride level… and greater increases in HDL cholesterol level… than those on the low-fat diet.”

Comparison of Weight Loss Among Named Diet Programs in Overweight and Obese Adults, 2014

Among 59 eligible articles reporting 48 unique randomized trials (including 7286 individuals) and compared with no diet, the largest weight loss was associated with low-carbohydrate diets… and low-fat diets… Weight loss differences between individual diets were minimal…”

The global obesity pandemic: shaped by global drivers and local environments, 2011

“Obesity is the result of people responding normally to the obesogenic environments they find themselves in. Support for individuals to counteract obesogenic
environments will continue to be important, but the priority should be for policies to reverse the obesogenic nature of these environments.”

Common genetic variants associated with cognitive performance identified using the proxy-phenotype method, 2014

“Turning from specific SNPs to the set of all 69 education-associated SNPs, we assess the explanatory power of a linear polygenic score that aggregates their coefficients… In pooled results from four family-based cohorts (4,463 individuals in total), we find that the score is significantly associated  with cognitive performance, with R2 ranging approximately from 0.2% to 0.4% across samples.”

Polygenic Inheritance and Gene Mapping, 2008

“Thus, in a recent set of collaborative studies, three labs performed GWAS using SNP-based approaches that involved many more test subjects in an effort to identify additional genes that contribute to human height. In these studies, the research teams examined at least 500,000 different SNPs in each of the more than 63,000 study subjects (Weedon et al., 2007; Gudbjartsson et al., 2008; Lettre et al., 2008; Weedon et al., 2008). Collectively, the teams identified 54 SNP variants that were strongly associated with height variation in the general population (Visscher, 2008).”

  • The “combined contribution to human height variation”: 2% – 3.7%.

Benzodiazepine use and risk of Alzheimer’s disease: case-control study, 2014

“Benzodiazepine ever use was associated with an increased risk of Alzheimer’s disease… The strength of association increased with exposure density… and with the drug half life… The stronger association observed for long term exposures reinforces the suspicion of a possible direct association, even if benzodiazepine use might also be an early marker of a condition associated with an increased risk of dementia.”

Efficacy of paracetamol for acute low-back pain: a double-blind, randomised controlled trial, 2014

“550 participants were assigned to the regular group (550 analysed), 549 were assigned to the as-needed group (546 analysed), and 553 were assigned to the placebo group (547 analysed). Median time to recovery was 17 days… in the regular group, 17 days… in the as-needed group, and 16 days… in the placebo group… We recorded no difference between treatment groups for time to recovery [from pain]… Adherence to regular tablets…, and number of participants reporting adverse events… were similar between groups.”

Young adult sequelae of adolescent cannabis use: an integrative analysis, 2014

“We recorded clear and consistent associations and dose-response relations between the frequency of adolescent cannabis use and all adverse young adult outcomes… Adverse sequelae of adolescent cannabis use are wide ranging and extend into young adulthood. Prevention or delay of cannabis use in adolescence is likely to have broad health and social benefits.”

  • Correlation does not equal causation. Alternative hypothesis: teens who have more stress/struggle/burden/issues are more likely to use cannabis and also more likely to have worse health outcomes. Also, the use of the term sequelae (“an aftereffect of a disease, condition, or injury” – Merriam-Webster) is deliberately pejorative.

Cancer Screening Rates in Individuals With Different Life Expectancies, 2014

A substantial proportion of the US population with limited life expectancy received prostate, breast, cervical, and colorectal cancer screening that is unlikely to provide net benefit. These results suggest that overscreening is common in both men and women, which not only increases health care expenditure but can lead to net patient harm.

The Appropriateness of More Intensive Colonoscopy Screening Than Recommended in Medicare Beneficiaries, 2014

“Screening Medicare beneficiaries more intensively than recommended is not only inefficient from a societal perspective; often it is also unfavorable for those being screened. This study provides evidence and a clear rationale for clinicians and policy makers to actively discourage this practice.

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