Table 1 Characteristics of prospective studies on caffeine intake in relation to low birth weight
First author, year | Country | Study design | Number of cases | Total number | Age | Exposure | Method of exposure assessment | Period of exposure assessed | Outcome | Adjustments |
|---|---|---|---|---|---|---|---|---|---|---|
Martin, 1987 [30] | United States | Cohort | 70 | 3,654 | <30 y: 69% | Caffeine | Interviewer-administered questionnaire | Early pregnancy | Low birth weight | Gestational age, ethnicity, parity, smoking |
-30 y: 31% | ||||||||||
Olsen, 1991 [27] | Denmark | Cohort | 391 | 11,591 | <30 y: 71% | Coffee | Self-administered questionnaire | First to second trimester | Low birth weight | Smoking, social group, parity, alcohol intake (did not adjust maternal age for this outcome but did for birth weight) |
-30 y: 29% | ||||||||||
Mills, 1993 [23] | United States | Cohort | 21 | 352 | <30 y: 48% | Caffeine | Interview | First, third trimesters and over the whole pregnancya | Low birth weighta, intrauterine growth restriction | Maternal age, income, education, pre-pregnancy weight, height, ethnicity, parity, smoking and alcohol intake |
-30 y: 52% | ||||||||||
Spinillo, 1994 [28] | Italy | Nested case-control | 347 | 1,041 | Case mean: 27.4 y | Coffee | NA | Variable, asked at prenatal visit or at delivery | Intrauterine growth restriction | Smoking, maternal age, marital status, parity, pre-pregnancy weight, BMI, weight gain, previous low birth weight, fetal sex, 1st trimester hemorrhage, hypertension, education, social class, alcohol intake |
Control mean: 29.3 y | ||||||||||
Grosso, 2001 [31] | United States | Cohort | 189 | 2,714 | <30 y: 38% | Caffeine | Interviewer-administered questionnaire | Before 16 weeks gestations | Intrauterine growth restriction | Smoking, height, antenatal weight gain, preeclampsia during index pregnancy, parity and bleeding during the third trimester. |
-30 y: 62% | ||||||||||
Bracken, 2003 [24] | United States | Cohort | 108 | 2,291 | <30 y: 47% | Caffeine | Interview | First trimestera & third trimesterb | Low birth weighta, intrauterine growth restriction | Maternal age, parity, number of prior pregnancies, marital status, ethnicity, education, height, smoking during the third trimester and weight |
-30 y: 53% | ||||||||||
CARE study group, 2008 [6] | United Kingdom | Cohort | 343 | 2,635 | Mean 30.0 y | Caffeine | Interviewer-administered questionnaire (validated) | First, second, third trimesters and over the whole pregnancya | Intrauterine growth restriction | Maternal age, weight, height, ethnicity, parity, neonatal gestational age at delivery and sex, smoking and alcohol intake |
Bakker, 2010 [25] | The Netherlands | Cohort | 331 | 7,346 | Mean 29.7 y | Caffeine | Self-administered questionnaire (postal) | Third trimester | Low birth weighta, Small for gestational age | Gestational age at visit, maternal age, education, ethnicity, parity, smoking, alcohol intake, height, BMI at intake, nutritional intake, folic acid supplement use, maternal pregnancy complications and fetal sex |
Sengpiel, 2013 [9] | Norway | Cohort | 4,503 | 59,123 | <30 y: 46% | Caffeine | Self-administered FFQ (validated) | First to second trimester | Small for gestational age | Maternal age, pre-pregnancy BMI, parity, history of preterm delivery, fetal sex, nausea during second trimester, smoking, passive smoking, nicotine intake from other sources, alcohol intake, energy intake, maternal education, marital status and household income |
-30 y: 54% |