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Study Title and Description

Association of maternal caffeine consumption with decrements in fetal growth.



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 Association of maternal caffeine consumption with decrements in fetal growth.
Author MB Bracken,EW Triche,K Belanger,K Hellenbrand,BP Leaderer,
Country
Year 2003
Numbers

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


Extraction Form: Reproductive Toxicity - Design Details
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Design Details
Question... Follow Up Answer Follow-up Answer
Refid 12615610
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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)? The current study was designed to test the hypothesis that caffeine consumption reduces fetal growth.
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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) Pregnant women were recruited in Connecticut and Massachusetts between September 1996 and January 2000. In all, 3,633 women were invited to participate; 2,478 (68.2 percent) enrolled, 639 (17.6 percent, same percentage by caffeine exposure) refused, 20 (0.6 percent) were not eligible at the time of the home interview, 72 (2.0 percent) miscarried before the interview, and 424 (11.7 percent) were lost to follow-up or could not be contacted for interview before the 24th-gestational-week eligibility limit expired. To obtain first-trimester exposures, we interviewed the respondent (usually at home) before the 25th week of gestation; detailed questions were asked about consumption of caffeinated and decaffeinated beverages before and each month during pregnancy. These calculations determined that a 10-ounce (1 ounce = 28.3 g) cup of drip-prepared coffee contained 100 mg of caffeine. Tea brewed for 3 minutes contained 42 mg of caffeine. Women were contacted throughout pregnancy to evaluate changes in health indicators and to validate exposures of interest; telephone, an intensively monitored, or a biochemically monitored group. For third-trimester exposures, each respondent was re-interviewed postnatally. Samples were analyzed for urinary caffeine by Labstat, Inc. (Kitchener, Ontario, Canada) using gas chromatography. Obstetric records were abstracted to identify pregnancy outcomes. Fetal growth retardation was defined as <10th percentile of birth weight for gestational age by using an external standard of birth weight for gestational age, adjusted for gender and ethnicity. low birth weight was defined as <2,500 g. Gestational age was calculated as completed days from the first day of the last menstrual period or the physician’s estimated date of delivery if the last menstrual period was uncertain. We gave preference to sonography estimates, which confirmed gestational age for 61.2 percent of the women. Preterm delivery was defined as <37th week of gestation. Odds ratios between caffeine consumption during the first and third trimesters and intrauterine growth retardation (IUGR), preterm delivery, and low birth weight were calculated from multiple logistic regression. Urinary caffeine was initially evaluated in quartiles (caffeine: <0.08, 0.08–0.24, 0.25–0.79, ≥ 0.80 mg/g creatinine). Final models were built by using backward elimination from models including potential confounders and exposures of interest.
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How many outcome-specific endpoints are evaluated? 3
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) IUGR/SGA
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List additional health endpoints (separately).
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List additional health endpoints (separately)
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Notes Fetal growth retardation was defined as <10th percentile of birth weight for gestational age by using an external standard of birth weight for gestational age, adjusted for gender and ethnicity. low birth weight was defined as <2,500 g. Gestational age was calculated as completed days from the first day of the last menstrual period or the physician’s estimated date of delivery if the last menstrual period was uncertain.
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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 Samples were analyzed for urinary caffeine by Labstat, Inc. (Kitchener, Ontario, Canada) using gas chromatography. Obstetric records were abstracted to identify pregnancy outcomes.
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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.) Average caffeine consumption: 0, 1-149, 150-299, >/=300 mg/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) age, parity, no. of prior pregnancies, marital status, race, education, height, smoking during the third trimester, and weight - "Nausea or vomiting in early pregnancy has been considered a possible confounder in studies of caffeine and spontaneous abortion, but, in this study, they were unrelated to any of the outcomes studied and occurred in 81.5 percent of respondents."
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Provide a general description of results (as reported by the authors). Self-reports of caffeine consumption in the first and third trimesters were not associated with intrauterine growth retardation, low birth weight, or preterm delivery. For every 1 mg/g creatinine increase in urinary caffeine, risk of intrauterine growth retardation was essentially unchanged (odds ratio (OR) = 0.96, 95% confidence interval (CI): 0.85, 1.08). In contrast, a 0.005 mg/g creatinine increase in urinary cotinine significantly increased risk (OR = 1.003, 95% CI: 1.001, 1.005). Mean birth weight was reduced by reported caffeine consumption (–28 g per 100 mg of caffeine consumed daily, 95% CI: –0.10, –0.46, p = 0.001) but not mean gestational age. Decaffeinated coffee did not increase risk for any perinatal outcome.
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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? [Appears to only have been done on unadjusted analyses and not presented beyond text.] First-trimester caffeine consumption was associated with increased risk of IUGR (linear-trend p = 0.009), with daily first-trimester caffeine consumption of ≥300 mg/day seeming to particularly increase the risk (odds ratio (OR) = 2.74, 95 percent confidence interval (CI): 1.52, 4.95). Similar increases in risk were shown for low birth weight (p for trend = 0.045), with caffeine consumption of ≥300 mg/day increasing the risk (OR = 2.55, 95 percent CI: 1.14, 5.70), and for preterm delivery (p for trend = 0.009), with increased risk in the highest caffeine consumption group (OR = 2.03, 95 percent CI: 1.03, 4.01). For third-trimester caffeine intake, these trends were less evident, and only low birth weight was statistically significant (p for trend = 0.037)
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What were the author's conclusions? This study provides reassurance that moderate caffeine consumption during pregnancy does not meaningfully influence fetal growth. Large quantities of caffeine should be avoided, but we found no evidence of risk from consumption of decaffeinated coffee. This small decrease in birth weight, observed for maternal caffeine consumption, is unlikely to be clinically important except for women consuming ≥600 mg of caffeine daily (approximately six 10-ounce (1 ounce = 28.3 g) cups of coffee).
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What were the sources of funding? This work was supported by grants DA05484 and AI41040 from the National Institutes of Health.
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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.  NOAEL = >/= 300 mg/day. Adjusted associations for caffeine consumption (>/= 300 mg/day) were: IUGR (OR = 1.75, 95% CI 0.81. 3.76), low birth weight (OR = 1.32, 95% CI 0.46, 3.78), and preterm delivery (OR = 1.67, 95% CI 0.74.3.81).
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Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot. Soda mg caffeine not reported
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What is the importance of the study with respect to the adverseness of the outcome? Critcal
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