DESIGN IN PRACTICE An experience in estimating the relationship - PowerPoint PPT Presentation

CASE-SPOUSE CONTROL STUDY DESIGN IN PRACTICE —— An experience in estimating the relationship between smoking and cancer deaths in Chinese Prof. Jingmei Jiang Dept. of Epidemiology & Biostatistics, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China 1

NEW STUDY DESIGN ! Case-spouse control design raised by Prof. Boqi Liu was incorporated into a nationwide retrospective mortality survey in China during 1989-1991. � ! The survey involved 103 study areas (24 major cities and 79 rural counties) and approximately one million adult deaths from all causes during 1986-1988. ! Within the study base, those who died of causes related to smoking were taken as cases, whereas surviving spouses of those who died from any conditions were taken as controls. Exposure information for both cases and controls was provided Case- spouse control study design � 2 by living spouses.

KEY MESSAGE � ! Smoking for health Life expectancy (year ) at age 35 44 Nonsmoker – Smoking causes early death; Smoker 42 40 – Smoking reduces life expectancy same 38 36 regardless of the poor and the rich; 34 32 30 – Smoking plays an important role in Urban female Urban male Rural female Rural male Total female Total male difference between male and female’s life. ! Smoking for cancer death – The area distribution of cancer mortality are not identical with that of smoking hazard, the tobacco-planting areas have higher smoking hazard; – Smoking causes common cancer deaths more; – The hazards of smoking on cancer death cumulate with age increasing. 3

Methodological study —— stability of new design � • New design and normal design RRs (PMR) was compared, the results showed consistence and stability regardless of sample size. • The new design, also suitable for small-scale study, is more sensitive than PMR design. sample size (from 100 to 25000) What we will do? � • This design from population to hospital 4

THANKS All contributors who created, carried out, rationalized, and developed the new design are acknowleged. � ! The application of this design in other countries and areas − Jha P, et al. A nationally representative case-control study of smoking and death in India. N Engl J Med . 2008. − Lam TH, et al. Mortality and smoking in Hong Kong. BMJ . 2001. − Gajalakshmi V, et al. Smoking and mortality from tuberculosis and other diseases in India. Lancet . 2003. − Sitas F, et al. Tobacco attributable deaths in South Africa. Tob Control . 2004. � ! As important reference for latter nationwide researches in China − Gu D, et al. Mortality attributable to smoking in China. N Engl J Med . 2009. − Yang G, et al. Smoking in China. JAMA .1999 . − Niu SR, et al. Emerging tobacco hazards in China. BMJ . 1998 . � 5 5