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Study Title and Description

The effect of caffeine consumption and nausea on the risk of miscarriage.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on reproductive and developmental outcomes?
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Primary Publication Information
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TitleData
Title The effect of caffeine consumption and nausea on the risk of miscarriage.
Author M Giannelli,P Doyle,E Roman,M Pelerin,C Hermon,
Country
Year 2003
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Reproductive Toxicity - Design Details
Arms
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Design Details
Question... Follow Up Answer Follow-up Answer
Refid 14629312
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What outcome is being evaluated in this paper? Reproductive and Development
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What is the objective of the study (as reported by the authors)? In the light of the important public health implications of a positive association of caffeine intake with miscarriage, the objective of the present analysis was to investigate the association between caffeine consumption, nausea and risk of miscarriage.
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) We examined the association with maternal caffeine intake in nulliparous women recruited during the years 1987–89 from the Royal Berkshire Hospital in Reading; cases were 160 women with a clinically diagnosed miscarriage and controls were 314 pregnant women attending for antenatal care. Information on caffeine consumption was collected using a structured questionnaire administered by a trained interviewer. Cases were interviewed, on average, 3 weeks after their miscarriage. To check the validity and reliability of responses at interview, a sample of study members was contacted and re-interviewed, and no evidence of bias in reporting as a function of case–control status was found. Controls attending for their first antenatal appointment were interviewed during their visit to hospital. For each beverage two continuous variables were created converting the number of cups consumed before and during pregnancy into mg of caffeine as follows: coffee, 107 mg per cup; tea, 34 mg per cup; cola, 47 mg per can. Four categories of caffeine intake were used, namely 0–150 mg/day, 151–300 mg/day, 301–500 mg/day, >500 mg/day. The effect of caffeine intake on the risk of miscarriage was estimated using logistic regression, with caffeine consumption </=150 mg/day as the baseline. Odds ratios (ORs) for miscarriage by caffeine were adjusted for maternal age, nausea in pregnancy and gestational age. The following potential risk factors were found not to act as confounders and were left out of the adjusted analyses: marital status, education, housing tenure, age at menarche, previous gravidity, previous miscarriage, difficulty becoming pregnant, smoking and alcohol consumption during pregnancy. Trends in dose of caffeine consumption, number of coffee cups, and severity of nausea were examined using chi-square tests for trend.
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How many outcome-specific endpoints are evaluated? 1
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Miscarriage
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List additional health endpoints (separately).
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List additional health endpoints (separately)
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Notes
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Clinical Clinical
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Physiological
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Other
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What is the study design? Case-Control
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Randomized or Non-Randomized?
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description Cases consisted of nulliparous women with a miscarriage clinically confirmed either by their GP or in hospital.
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Caffeine (general) Caffeine (general)
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Coffee Coffee
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Chocolate
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Energy drinks
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Gum
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Medicine/Supplement
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Soda Soda
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Tea Tea
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Measured
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Self-report Self-report
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Children
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Adolescents
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Adults
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Pregnant Women Pregnant Women
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Four categories of caffeine intake were used, namely 0–150 mg/day, 151–300 mg/day, 301–500 mg/day, >500 mg/day. </=150 mg/day as the baseline
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) Odds ratios (ORs) for miscarriage by caffeine were adjusted for maternal age, nausea in pregnancy and gestational age. The following potential risk factors were found not to act as confounders and were left out of the adjusted analyses: marital status, education, housing tenure, age at menarche, previous gravidity, previous miscarriage, difficulty becoming pregnant, smoking and alcohol consumption during pregnancy.
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Provide a general description of results (as reported by the authors). The risk of miscarriage progressively increased when caffeine intake during pregnancy exceeded 300 mg/day (test for trend P=0.0025).Compared with a maternal caffeine intake of <151 mg/day, we found evidence that caffeine consumption >300 mg/day doubled the risk of miscarriage. Adjusted odds ratios were 1.94 [95% CI 1.04, 3.63] for 301–500 mg/day and 2.18 [95% CI 1.08, 4.40] for >500 mg/day. This effect could not be explained by nausea in pregnancy. Nausea appeared to be strongly independently associated with a reduced risk of miscarriage (test for trend P<0.0001). There was no evidence that prepregnancy caffeine consumption affected the risk. The risk of miscarriage increased by approximately twice when one or more cups of coffee ( >107 mg caffeine) per day were consumed (test for trend P=0.0016). Drinking >3 cups of tea (>102 mg caffeine) or two cans of cola (>94 mg caffeine) did not significantly influence the risk of miscarriage.
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Did the authors perform a dose-response analysis (or trend/related analysis)? Yes
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What were the authors's observations re: trend analysis? The risk of miscarriage progressively increased when caffeine intake during pregnancy exceeded 300 mg/day (test for trend P=0.0025).
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What were the author's conclusions? 1. High caffeine consumption during pregnancy (>300 mg/day), in particular coffee consumption, is an independent risk factor for increased risk of miscarriage. 2. Nausea is an independent protective factor for a lower risk of miscarriage. The policy implications of these results are that pregnant women may be able to lower their risk of miscarriage by reducing coffee intake during early pregnancy.
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What were the sources of funding? None reported
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What conflicts of interest were reported? None reported
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Does the exposure (dose) need to be standardized to the SR? No
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Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest).
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List all the endpoint(s) followed by the dose (mg) which will be used in comparison to Nawrot.  Characterize value as LOAEL/NOAEL, etc. if possible.  LOAEL = 301-500 mg/day for miscarriage
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Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot. 151-300 mg/day: adjusted OR 1.19 [95% CI 0.67, 2.12] 301-500 mg/day: adjusted OR 1.94 [95% CI 1.04, 3.63] >500 mg/day: adjusted OR 2.18 [95% CI 1.08, 4.40]
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What is the importance of the study with respect to the adverseness of the outcome? Critcal
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