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Study Title and Description

The associations of maternal caffeine consumption and nausea with spontaneous abortion.



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 associations of maternal caffeine consumption and nausea with spontaneous abortion.
Author W Wen,XO Shu,DR Jacobs,JE Brown,
Country
Year 2001
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 11138817
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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)? We examined the relation of caffeine consumption and nausea with spontaneous abortion using data from the Diana Project, a population-based, prospective study that included 968 women enrolled before pregnancy.
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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) Participants were from the Diana Project - recruited during the years 1989–1992 from a population of women 22–35 years of age. Dietary intake was assessed using the Willett food frequency questionnaire. Women completed the vital data questionnaires once and the food frequency questionnaire three times, then every 3 months until conception occurred, and then monthly during pregnancy. Medical records were used to abstract information regarding parity spontaneous abortion. Caffeine content was assigned to beverages as follows: regular coffee, 139.2 mg per cup; tea, 64.0 mg per cup; cola, 46.0 mg per 12 oz, hot chocolate, 16.0 mg per cup; and caffeinated diet soda, 46.0 mg per cup. Caffeine content of products that contain chocolate (for example, brownies and chocolate syrup) was also included in total caffeine intake. Mean caffeine consumption per day was calculated for each month. Four categories of consumption were defined (<20, 20–99, 100–299, and >/=300 mg per day). Nausea status (yes/ no) and its duration (days) were recorded monthly. Analyses on spontaneous abortion included mean daily caffeine consumption before pregnancy, in the first trimester of the pregnancy, or up to the date of spontaneous abortion if it occurred before the end of the first trimester; analyses were further stratified by timing of the caffeine consumption in relation to occurrence of nausea. We calculated the risk of spontaneous abortion for each category of risk predictor by dividing the number of women who had a spontaneous abortion by the total number of women in the corresponding group. We used the Mantel-Haenszel procedure to estimate risk ratios and their 95% confidence intervals (95% CIs). To show trend, we present spline-smoothed trend curves using a method described by Greenland.
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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) Spontaneous abortion
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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? Cohort
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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 Medical records
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Caffeine (general) Caffeine (general)
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Coffee Coffee
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Chocolate 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.) Mean caffeine consumption: <20, 20–99, 100–299, and >/=300 mg per day
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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) Considered some demographic factors, smoking and alcohol drinking, and other selected characteristics of women under study such as parity and body mass index as potential confounding factors (Table 1) because of their reported relation to maternal caffeine consumption and spontaneous abortion. [Note the following are listed in Table 1 but not specifically identified as having been adjusted for: race, employed for pay, marriage, educational level, household income, parity, smoking at enrollment, alcohol intake at enrollment, age at enrollment, prepregnant weight, height, prepregnant BMI. Data from vital questionnaires were collected only once. ]
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Provide a general description of results (as reported by the authors). Despite an average reduction in caffeine intake during the first trimester of the pregnancy, the risk of spontaneous abortion was higher among women who reported relatively higher caffeine consumption. As compared with caffeine consumption of <20 mg per day, risk ratios for spontaneous abortion associated with consumption of 20–99, 100–299, >/=300 mg caffeine daily were 1.5 (95% CI = 0.8 –2.7), 2.0 (95% CI = 1.0–4.1), and 2.5 (95% CI = 1.0–6.4), respectively. Stratifying caffeine consumption during the first trimester by nausea status, we found that the association between spontaneous abortion and caffeine consumption was restricted to the period after nausea started (the median caffeine consumption was 32.6 mg per day in the abortion group vs 17.9 mg per day in the livebirth group; risk ratio = 5.4 (95% CI = 2.0 –14.6) for caffeine consumption >/=300 mg per day compared with <20 mg per day). Neither caffeine consumption before nausea in women who ever reported nausea nor caffeine consumption in women who never reported nausea was materially associated with an increased risk of spontaneous abortion. The first trimester curve showed an increasing trend of the risk of spontaneous abortion as maternal caffeine consumption rose. A more striking trend was observed for the After nausea curve. The No nausea curve showed a slight trend of decreasing risk of spontaneous abortion with increasing maternal caffeine consumption.
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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 first trimester curve showed an increasing trend of the risk of spontaneous abortion as maternal caffeine consumption rose. A more striking trend was observed for the After nausea curve. The No nausea curve showed a slight trend of decreasing risk of spontaneous abortion with increasing maternal caffeine consumption.
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What were the author's conclusions? Maternal caffeine consumption before pregnancy, or in women without nausea, did not increase the risk of spontaneous abortion, whereas maternal caffeine consumption during the first trimester after nausea started might increase risk of spontaneous abortion. In summary, our study suggests that spontaneous abortion is unrelated to maternal caffeine consumption before conception, before nausea starts in the first trimester of the pregnancy, or in women who did not experience nausea. Maternal caffeine consumption after nausea starts in the first trimester was associated with an increased risk of spontaneous abortion.
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What were the sources of funding? The research reported here was supported by National Institute of Child Health and Human Development Grant R01 HD19724.
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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.  First trimester all participants, nausea or not: risk ratio = 2.0 (95% CI = 1.0-4.1) for 100-200 mg/day and 2.5 (95% confidence interval = 1.0 –6.4) for >/=300 mg/day. The authors do not comment on significance; based on these data a LOAEL of 100 mg/day could be considered. First trimester after nausea: risk ratio = 5.4 (95% confidence interval = 2.0 –14.6) for caffeine consumption >/=300 mg per day compared with <20 mg per day. The authors do not comment on significance; based on these data a LOAEL of 300 mg/day could be considered.
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Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot. Caffeine content was assigned to beverages as follows: regular coffee, 139.2 mg per cup; tea, 64.0 mg per cup; cola, 46.0 mg per 12 oz, hot chocolate, 16.0 mg per cup; and caffeinated diet soda, 46.0 mg per cup. Additional analyses are provided in Table 3 of the report for caffeine intake with or without nausea and before or after nausea.
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What is the importance of the study with respect to the adverseness of the outcome? Critcal
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