A case control study of household tobacco smoke and sudden infant death syndrome

Question

A case control study of household tobacco smoke and sudden infant death syndrome in the state of NJ found an odds ratio (OR) of 1.7, so the odds of exposure to household tobacco smoke among children with SIDS was 1.7 times that of tobacco smoke exposure among children who did not have SIDS. The SIDS cases came from a state registry of all SIDS deaths. The controls were selected by identifying a child born on the same day from state birth records, then inviting that parent/child to participate by telephone and letter.

Describe the potential bias from the following situations, including how it would have biased the true OR, and what it means regarding your resulting OR.

(e.g. bias because of ___________ may have resulted in bias away/toward the null, and therefore the OR reported may be an over/under estimate of the true OR).

1.)The participation rate among parents of cases was 90%, and the participation rate of parents of controls was 66%. From the birth certificate data, we were able to assess the maternal education of participants and non-participants, and learned that 70% of participants had a college education while only 40% of non-participants did.

2.) The interviewers knew the case status, since it is apparent when doing the interview if it was a grieving parent or one with a living baby.

3.)The tendency to diagnose unexplained infant deaths as SIDS may vary from hospital to hospital in NJ.

Explanation / Answer

ANswer to question# 1)

there is bias due to difference in the maternal education level of the two groups. this leads to non-participation of the parents and hence leads to a biased outcome

Such a biasedness leads to increase in the OR

.

Answer to questioN# 2)

Such a kind of bias is called interview biased, where the interviewer already is aware of the inclination of results.

Such a bias goes in favor of OR.

Answer to question# 3)

This biasedness is caused due to error in the data at the primary source

The data of the SIDS may not be appropriate , as it is base don personal judgement of different hospitals and may vary accordingly

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.