Vitamin C protection against heart disease doubted

High blood levels of vitamin C have been associated with lower Heart Attack risk, but now UK researchers say socioeconomic status may account for the relationship.

In other words, well-off people have less illness and high levels of vitamins, but the two are not necessarily connected.

While studies of a cross-section of a population have tied vitamin C intake to coronary heart disease, controlled trials to see if vitamin C wards off heart trouble have shown no effect, Dr. Debbie A. Lawlor of the University of Bristol and colleagues note in the medical journal Heart.

The researchers previously suggested that high levels of vitamin C might be related to higher socioeconomic class in childhood and adult life. They conducted the current study to examine the relationship among serum vitamin C, life course socioeconomic position and coronary heart disease risk.

The researchers analyzed data from the British Women's Heart and Health Study. Data for 3073 women were available on vitamin C concentrations and socioeconomic class, as measured by 10 indicators of life course socioeconomic position. Indicators included father's occupational social class, having a bathroom and hot water in the childhood home, age at leaving full-time education and pension arrangements.

During follow-up, which lasted an average of 4 years, 158 of the women developed coronary heart disease. With each additional adverse life course socioeconomic indicator, vitamin C levels dropped while rates of coronary Heart disease increased, the researchers report.

Specifically, the rate of coronary heart disease was the equivalent of 13.2 cases per 1,000 women per year for women with zero to four adverse socioeconomic indicators and 15.2 per 1,000 for women with five or more adverse indicators.

When the researchers factored in socioeconomic status, the relationship between vitamin C levels and heart disease risk disappeared.

"Our results are supportive of randomized controlled evidence that there is no important causal association between vitamin C and coronary heart disease," Lawlor and colleagues conclude.

SOURCE: Heart, August 2005.