Study Title and Description
Caffeinated beverage and soda consumption and time to pregnancy.
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?|
Primary Publication Information
|Title||Caffeinated beverage and soda consumption and time to pregnancy.|
|Author||EE Hatch,LA Wise,EM Mikkelsen,T Christensen,AH Riis,HT Sørensen,KJ Rothman,|
Secondary Publication Information
There are currently no secondary publications defined for this study.
Extraction Form: Reproductive Toxicity - Design Details
No arms have been defined in this extraction form.
|Question... Follow Up||Answer||Follow-up Answer|
|What outcome is being evaluated in this paper?||Reproductive and Development|
|What is the objective of the study (as reported by the authors)?||Many epidemiologic studies have evaluated the association between caffeine and fertility, with inconsistent results. Some studies suggest that various caffeine-containing beverages may affect fertility differently. We evaluated the relation between time to pregnancy and consumption of caffeinated beverages and soda in a large prospective cohort study of Danish women who were trying to become pregnant.|
|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)||The Snart Gravid study is an Internet-based prospective cohort study. We evaluated the relation of caffeine, coffee, tea, and sodas with time to pregnancy in a prospective cohort study of 3628 women planning a pregnancy, in Denmark. Women who had been trying to conceive for no more than 12 months reported beverage intake at baseline and every 8 weeks during follow-up until they became pregnant or for up to 12 cycles. We estimated total caffeine content by assuming that one serving of coffee contained 141 mg of caffeine; 1 serving of decaffeinated coffee, 5 mg; 1 serving of regular tea, 56 mg; 1 serving of regular cola, 51 mg; and 1 serving of diet cola, 66 mg of caffeine. We used discrete-time Cox proportional hazards regression to estimate fecundability ratios (FRs) and 95% confidence intervals (CIs), controlling for potential confounders.|
|How many outcome-specific endpoints are evaluated?||1|
|What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately)||Fecundity (time to pregnancy)|
|List additional health endpoints (separately).|
|List additional health endpoints (separately)|
|Notes||We estimated time to pregnancy in cycles based on the following formula: (days of trying at study entry/cycle length) + ([ LMP date from most recent follow-up questionnaire - date of baseline questionnaire completion)/ cycle length]+1).|
|What is the study design?||Cohort|
|Randomized or Non-Randomized?|
|What were the diagnostics or methods used to measure the outcome?||Both|
|Optional: Name of Method or short description||Self-reported|
|Caffeine (general)||Caffeine (general)|
|Pregnant Women||Pregnant Women|
|What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.)||Caffeine mg/day: <100, 100–199, 200–299, >/=300|
|What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models. Copy from methods)||We collected data on potential covariates in the baseline questionnaire, including age, partner’s age, education and income, frequency of intercourse, menstrual characteristics, reproductive history, height, weight, medical history, physical activity, smoking history, and alcohol intake. Data on lifestyle factors were updated in each follow-up questionnaire. We calculated body mass index (BMI) as weight (kg)/height (m2). Self-reported data on height and weight were validated in a subset of women using data from the Danish Birth Registry, with high reproducibility (Pearson r _x0003_ 0.96).35 We asked about time spent per week doing vigorous and moderate physical activity and estimated total metabolic equivalents (METs) of physical activity per week by summing the METs from moderate exercise (hours per week multiplied by 3.5) and vigorous exercise (hours per week multiplied by 7.0|
|Provide a general description of results (as reported by the authors).||Overall, we found little association between total caffeine intake (mg/day) and fecundability, using either caffeine exposure at baseline or updating exposure during follow-up; adjusted FRs for time-varying data ranged from 0.98 to 1.07 for categories of consumption < 100 mg/day compared with >100 mg/day. We did not find a monotonic trend of coffee consumption on fecundability, and all FRs for coffee consumption were close to 1.0, whether using baseline or time-varying data. There was little relation between fecundability and caffeine intake of >/=300 mg/day compared with <100 mg/day (FR = 1.04, 95% CI 0.90 –1.21).|
|Did the authors perform a dose-response analysis (or trend/related analysis)?||No|
|What were the authors's observations re: trend analysis?|
|What were the author's conclusions?||In summary, we found little overall relation between caffeine or coffee consumption and time to pregnancy. We did, however, find some evidence for decreased fecundability among women who consumed sodas and increased fecundability among women who drank tea. We caution that these associations may reflect unmeasured confounding by diet or other lifestyle factors.|
|What were the sources of funding?||This study was supported by the National Institute for Child Health and Development (R21-050264 and R01-060680) and the Danish Medical Research Council (271-07-0338). The authors reported no other financial interests related to this research.|
|What conflicts of interest were reported?||None reported|
|Does the exposure (dose) need to be standardized to the SR?||No|
|Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest).|
|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.||Fecundity (time to pregnancy) NOAEL = >/=300 mg/day|
|Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot.||FRs at baseline and by time-varying were similar; for >/=300 mg/da, FR = 1.06 (0.92-1.23) and 1.04 (0.90-1.21), respectively.|
|What is the importance of the study with respect to the adverseness of the outcome?||Critcal|
No baseline characteristics have been defined for this extraction form.
Results & Comparisons
No Results found.
|Arm or Total||Title||Description||Comments|
No quality dimensions were specified.
No quality rating data was found.