title: Did it fall or was it pushed? The contribution of trends in established risk factors to the decline in premature coronary heart disease mortality in New Zealand.
abstract: OBJECTIVE
  To estimate the contribution of trends in three risk factors--systolic blood pressure (SBP), total blood cholesterol (TBC) and cigarette smoking--to the decline in premature coronary heart disease (CHD) mortality in New Zealand from 1980-2004.
  
  
  METHODS
  Risk factor prevalence data by 10-year age group (35-64 years) and sex was sourced from six national or Auckland regional health surveys and three population censuses (the latter only for smoking). The data were smoothed using two-point moving averages, then further smoothed by fitting quadratic regression equations (SBP and TBC) or splines (smoking). Risk factor/CHD mortality hazard ratios estimated by expert working groups for the World Health Organization Global Burden of Disease Study 2001 were used to translate average annual changes in risk factor prevalences to the corresponding percentage changes in premature CHD mortality. The expected trends in CHD mortality were then compared with the observed trend to estimate the contribution of each risk factor to the decline.
  
  
  RESULTS
  Approximately 80% (73% for males, 87% for females) of the decline in premature CHD mortality from 1980 to 2004 is estimated to have resulted from the joint trends in population SBP and TBC distributions and smoking prevalence. Overall, approximately 42%, 36% and 22% of the joint risk factor effect was contributed by trends in SBP, TBC and smoking respectively.
  
  
  CONCLUSIONS
  Our estimate for the joint risk factor contribution to the CHD mortality decline of 80% exceeds those of two earlier New Zealand studies, but agrees closely with a similar Australian study. This provides an indicator of the scope that still remains for further reduction in CHD mortality through primary and secondary prevention.
authors.affiliation: Public Health Intelligence, Ministry of Health, New Zealand. martin_tobias@moh.govt.nz
authors.forename: Martin
authors.initials: M
authors.lastname: Tobias
authors.forename: Richard
authors.initials: R
authors.lastname: Taylor
authors.forename: Li-Chia
authors.initials: LC
authors.lastname: Yeh
authors.forename: Ken
authors.initials: K
authors.lastname: Huang
authors.forename: Stewart
authors.initials: S
authors.lastname: Mann
authors.forename: Norman
authors.initials: N
authors.lastname: Sharpe
mesh_terms: D000328:Adult; D000367:Age Factors; D003324:Coronary Artery Disease / Q000453:epidemiology / Q000401:mortality*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D015995:Prevalence; D012307:Risk Factors; D040242:Risk Reduction Behavior; D012907:Smoking / Q000009:adverse effects; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
chemical_list: D014028:Tobacco Smoke Pollution