Transcript Journal Club Alcohol and Health: Current Evidence May-June 2006 www.alcoholandhealth.org Featured Article Maternal coffee and alcohol consumption during pregnancy, parental smoking and risk of childhood acute leukemia Menegaux.

Journal Club
Alcohol and Health: Current Evidence
May-June 2006
www.alcoholandhealth.org
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Featured Article
Maternal coffee and alcohol
consumption during pregnancy,
parental smoking and risk of
childhood acute leukemia
Menegaux F, et al. Cancer Detect and Prev. 2005;29:487–493.
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Study Objective
To examine the association between…
– alcohol use, coffee drinking, and
smoking during pregnancy and
– childhood acute lymphoid leukemia
(ALL) and acute nonlymphoid leukemia
(ANLL)
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Study Design
• Case-control study of children hospitalized with…
– newly diagnosed acute leukemia (n=280) or
– for a disease other than cancer/birth defect (n=288)
• All subjects from the same hospitals; controls
mainly from orthopedic departments
• Interviews of mothers that covered alcohol use
during pregnancy and other topics (e.g., medical
history)
• Analyses adjusted for potential confounders
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Assessing Validity of an
Article About Harm
• Are the results valid?
• What are the results?
• How can I apply the results to
patient care?
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Are the Results Valid?
• Did the investigators demonstrate similarity in all
known determinants of outcomes? Did they
adjust for differences in the analysis?
• Were exposed patients equally likely to be
identified in the two groups?
• Were the outcomes measured in the same way in
the groups being compared?
• Was follow-up sufficiently complete?
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Did the investigators demonstrate similarity in
all known determinants of outcomes? Did they
adjust for differences in the analysis?
• Cases and controls were compared on demographic
factors (they were similar).
• Analyses were adjusted for these factors while
examining effects of alcohol use, smoking, and
coffee drinking separately.
• Other risk factors for leukemia were not reported.
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Were exposed patients equally likely
to be identified in the two groups?
 Researchers described use of standardized
questionnaires and similar interviewing conditions
for both groups.
 But, recall bias may have made identifying the
exposure more likely in mothers of children with
leukemia.
 When asked about exposures during pregnancy, a mother
with a child with newly diagnosed leukemia may be more
likely to recall the exposures than would a mother of a
child with an acute injury.
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Were the outcomes measured in the
same way in the groups being compared?
•
Cases and controls were drawn from the
same hospitals.
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Was follow-up sufficiently complete?
• There was no follow-up.
– This was a retrospective case-control study.
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What are the Results?
• How strong is the association between
exposure and outcomes?
• How precise is the estimate of the risk?
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How strong is the association
between exposure and outcomes?
Odds Ratios (ORs)* and 95%
Confidence Intervals
Exposure During Pregnancy
ALL
ANLL
Any alcohol use
2.0 (1.4–3.0)
2.6 (1.2–5.8)
<=3 cups of coffee/day
1.1 (0.7–1.8)
1.6 (0.6–4.3)
4–8 cups of coffee/day
2.4 (1.3–4.7)
2.8 (0.7–10.4)
Any smoking
0.9 (0.6–1.4)
1.0 (0.4–2.3)
*Compared with no use and in analyses adjusted for age, sex, hospital, and ethnicity
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How strong is the association between
exposure and outcome? (cont.)
• Results did not differ when analyses were adjusted
for…
– any of the substances examined,
– profession,
– education,
– early infection history,
– breast-feeding,
– maternal history of fetal loss, or
– familial history of cancer.
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How precise is the estimate of the risk?
• Confidence intervals:
– for any alcohol use and ALL: 1.4–3.0
– for any alcohol use and ANLL: 1.2–5.8
– for drinking 4–8 cups of coffee per day and
ALL: 1.3–4.7
• These intervals do not include 1, indicating
statistical significance.
• However, they are wide, particularly in the cases
of alcohol and ANLL and coffee and ALL.
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How Can I Apply the Results to
Patient Care?
• Were the study patients similar to the patients in
my practice?
• Was the duration of follow-up adequate?
• What was the magnitude of the risk?
• Should I attempt to stop the exposure?
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Were the study patients similar to the
patients in my practice?
• The children were identified in 4 hospitals in
France.
• How they might differ from other children
with leukemia, aside from geography, is not
known.
• Most of the children were Caucasian.
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Was the duration of follow-up adequate?
• There was no follow-up.
• Children with leukemia were younger than
controls. Although unlikely, it is possible that…
– results might have been different if follow-up
(time since pregnancy and prenatal exposure)
had been similar.
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What was the magnitude of the risk?
• The risk of leukemia was 2–3 times greater
for children of women who…
– drank alcohol or 4–8 cups of coffee per day
during pregnancy.
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Should I attempt to stop the exposure?
• Pregnant women should not drink alcohol.
• This recommendation is primarily because of
the risk of fetal alcohol effects and syndrome.
• Leukemia may represent an additional, but
rarer, risk of alcohol consumption.
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Should I attempt to stop the exposure
(cont.)?
• Both the alcohol and coffee findings should
be considered hypothesis generating.
• This study alone should not determine
choices around coffee consumption.
– Data are sparse in this area, and further
study is needed.
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