In study aimed at examining whether vitamin deficiency was associated with birth
ID: 3365045 • Letter: I
Question
In study aimed at examining whether vitamin deficiency was associated with birth defects, an investigator reviewed the birth certificates during a single year in a large U.S. county and identified 300 infants born with neural tube defects (NTDs). A total of 800 other births without NTD were selected at random from the birth certificates as the control group. Mothers were given a dietary questionnaire. Among mothers who gave birth to an infant with an NTD, 120 reported no use of supplementary vitamins; a total of 240 control mothers did not use a vitamin supplement. Calculate and interpret the odds ratio for the association of vitamin use and NTDs. A. 1.56; Mothers of infants born with NTD were 1.56 times more likely to take a vitamin supplement than mothers of infants born without NTD. B. 2.7; Mothers who did not take a vitamin supplement were 2.7 times as likely to have an infant born with NTDs than women who took a vitamin supplement. C. 0.55; Mothers who did not take a vitamin supplement were 0.55 times as likely to have an infant born with NTDs as women who took a vitamin supplement. D. 0.64; Mothers of infants born with NTD were 0.64 times as likely to report taking a vitamin supplement than mothers of infants born without NTD.
Explanation / Answer
SUPPLEMENT
NTD
TOTAL
CASES
CONTROLS
YES
a=180
b=560
740
NO
c=120
d=240
360
TOTAL
300
800
1100
Odds ratio = ad/bc = (180*240)/(560*120) =43200/67200=0.64
Odds ratio = 0.64
Answer: (D)
0.64; Mothers of infants born with NTD were 0.64 times as likely to report taking a vitamin supplement than mothers of infants born without NTD.
SUPPLEMENT
NTD
TOTAL
CASES
CONTROLS
YES
a=180
b=560
740
NO
c=120
d=240
360
TOTAL
300
800
1100
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.