Heart Health Watch

The Impact of Diet and Genes on CV Risk

A study published in the October 2011 issue of the journal PloS Medicine suggests that eating healthy can mitigate the cardiovascular (CV) risk associated with certain genetic variations. More specifically, the study sought to determine what impact diet had in people with single nucleotide polymorphisms (SNPs, pronounced “snips”) in a chromosomal region called 9p21.

SNPs are single DNA base pair substitutions that occur at an allele frequency greater than or equal to 1% in a population. It has been demonstrated that certain populations with SNPs in the 9p21 region have an increased risk of developing CV disease. In this study, people who possessed the genetic variant but ate diets rich in fresh fruits and vegetables attenuated their CV risk.

To investigate this gene-environment interaction, researchers analyzed data from the INTERHEART and FINRISK studies. Data were drawn from approximately 8000 individuals from the INTERHEART study and approximately 19,000 Finnish individuals from the FINRISK study. Two separate analyses were conducted and the data were not pooled. Eating habits were measured with food frequency questionnaires.

The subjectively labeled “prudent” diet in the INTERHEART study included raw vegetables, fruits, green leafy vegetables, nuts, desserts, and dairy products. In the FINRISK study, participants were asked how often they ate fresh vegetables, fresh fruits, or fresh or frozen berries. The two analyses yielded similar results.

Despite the promising findings, the authors note that the study has its limitations. They note that it would be difficult to replicate these results, because dietary habits can vary greatly. Because participants may have forgotten what they ate, the authors also cite recall bias as a potential limitation. Nonetheless, the study sheds light on the important influence diet and genes have on CV risk.

ADHD Drugs Not Associated with Serious CV Events

In February 2007, the FDA issued a press release stating that all manufacturers of drugs approved for the treatment of attention-deficit/hyperactivity disorder (ADHD) were required to create medication guides explaining the potential risk of CV and psychiatric adverse events. A recent study may allay some parents’ fears that ADHD drugs such as Adderall (dextroamphetamine and amphetamine) or Ritalin (methylphenidate) may cause heart problems, however.

Published in The New England Journal of Medicine in November 2011, the study showed that there was no association between current usage of ADHD drugs and an increased risk of serious CV events (adjusted hazard ratio, 0.75; 95% confidence interval, 0.31-1.85). Serious CV events included sudden cardiac death, acute myocardial infarction, and stroke.

Funded by the Agency for Healthcare Research and Quality and the FDA, the study collected data for approximately 1.2 million children and young adults aged 2 to 24 years from 4 different health plans. The study was retrospective in design and employed Cox regression models for its hazard ratios. Event rates were similar for nonusers, former users, and current users. The authors note, however, that the low number of CV events limited their ability to detect differences among individual drugs, end points, and subgroups. Despite this, the authors stand by the robustness of their findings, concluding that “the absolute magnitude of any increased risk would be low.”

HPV Associated with Increased CV Disease Risk

According to the Centers for Disease Control and Prevention, there are approximately 6 million new cases of human papillomavirus (HPV) infection each year and it is said that at least 50% of sexually active men and women get it in their lifetime. A recent study suggests this common sexually transmitted disease may have other adverse consequences.

In a study following 2450 US women aged 20 to 59 years, researchers found that the presence of vaginal HPV DNA taken via self-collected swab was positively associated with CV disease. Thirty-nine of the 60 women with coronary artery disease were positive for HPV DNA. It was found that those infected with general types of HPV and cancer-associated types of HPV were more likely to have CV disease than those who were not infected (odds ratios 2.30 and 2.86, respectively). Both results were statistically significant.

The results were controlled for comorbidities, CV risk factors, and other potentially confounding variables, but a cause-andeffect relationship has yet to be demonstrated. Currently, there are 2 FDA-approved vaccines available for certain HPV strains. Gardasil is approved for protection against HPV strains 6, 11, 16, and 18; Cervarix is approved for protection against HPV strains 16 and 18. PT