Does sex matter in the associations between classic risk factors and fatal coronary heart disease in populations from the Asia-Pacific region?
BACKGROUND
There is much interest in promoting healthy heart awareness among women. However, little is known about the reasons behind the lower rates of heart disease among women compared with men, and why this risk difference diminishes with age. Previous comparative studies have generally had insufficient numbers of women to quantify such differences reliably.


METHODS
We carried out an individual participant data meta-analysis of 39 cohort studies (32 from Asian countries and 7 from Australia and New Zealand). Cox models were used to estimate hazard ratios (HR) for coronary death, comparing men to women. Further adjustments were made for several proven coronary risk factors to quantify their contributions to the sex differential. Sex interactions were tested for the same risk factors.


RESULTS
During 4 million person-years of follow-up, there were 1989 (926 female) deaths from coronary heart disease (CHD). The age-adjusted and study-adjusted male/female HR (95% confidence interval [95% CI]) was 2.05 (1.89-2.22). At baseline, 54% of men vs. 7% of women were current smokers; hence, adjustment for smoking explained the largest component (20%) of this HR. A significant sex interaction was observed between systolic blood pressure (SBP) and CHD mortality such that a 10 mm Hg increase was associated with a 15% greater increase in the relative risk (RR) of coronary death in women compared with men (p = 0.002).


CONCLUSIONS
Only a small amount of the sex differential in coronary death could be explained by differences in the prevalence of classic risk factors. Alternative explanations are required to explain the age-related attenuation of the sex difference in CHD risk.
Huxley
Rachel
R
The George Institute for International Health, University of Sydney, NSW, Australia. rhuxley@thegeorgeinstitute.org
Woodward
Mark
M
Barzi
Federica
F
Wong
Jean Woo
JW
Pan
Wen Harn
WH
Patel
Anushka
A
D017677:Age Distribution; D000368:Aged; D001208:Asia / Q000453:epidemiology; D001315:Australia / Q000453:epidemiology; D002784:Cholesterol; D015897:Comorbidity; D016001:Confidence Intervals; D003327:Coronary Disease / Q000209:etiology* / Q000401:mortality; D048909:Diabetes Complications / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D009765:Obesity / Q000453:epidemiology; D016017:Odds Ratio; D016016:Proportional Hazards Models; D018570:Risk Assessment; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D016387:Women's Health
D002784:Cholesterol