Table 1.
Characteristics of study methods for the association between parental pesticide exposure and hypospadias
| Lead author and year | Study population and period | Subject selection (case:control) | Exposure assessment | Covariate adjustment* | Maternal exposure |
Paternal exposure |
||
|---|---|---|---|---|---|---|---|---|
| Exposure levels | Exposure period | Exposure levels | Exposure period | |||||
| Schwartz 1986 [49] | California, USA 1975–1978 | Hospital (12:2451) | Medical chart review | NO | Agricultural occupation vs non-agricultural occupation | Prenatal | Agricultural occupation vs non-agricultural occupatior | Prenatal |
| Schnitzer 1995 [43] | Georgia, USA 1968–1990 | Birth register (463:2388) | Parental interview | NO | Farm manager or worker (yes/no) | During 2 years before birth | ||
| Olshan 1991 [44] | British Columbia 1952–1973 | Birth defects registry (838:28,830) | Occupation recorded on birth record | YES | Occupation “farm managers and workers’’ (yes/no) | Birth | ||
| Garcia 1999 [47] | Spain 1993–1994 | Hospitals (18:18) | Parental interview | YES | Agricultural work ever (yes/no) Agricultural work during acute risk periods (yes/no) |
Ever/1 month prior through first trimester | Pesticide application ever (yes/no) Pesticide application in critical period (yes/no) |
Ever/3 months prior through first trimester |
| Carbone 2006 [50] | Ragusa, Italy 1998–2002 | Pediatric services (43:203) | Parental interview and JEM | YES | Work in agriculture (yes/no) Exposure to pesticidesa |
Before/during pregnancy | Work in agricultureb | Before/during pregnancy |
| Pierik 2004 [46] | The Netherlands 1991–2001 | Child health care centers (56:313) | Parental interview and JEM | NO | Probable pesticide exposure (yes/no) | First trimester | Exposure to pesticidesc Probable pesticide exposure (yes/no) | Periconception |
| Weidner 1998 [45] | Denmark 1983–1992 | Birth cohort (1345:23,273) | Maternal interview | YES | Farmer (yes/no) Gardener (yes/no) | Occupation during year of conception | Farmer (yes/no) Gardener (yes/no) | Occupation during year of conception |
| Zhu 2006 [30] | Denmark 1997–2003 | Birth cohort (172: 62,432) | Maternal interview | NO | Farmer (yes/no) Gardener (yes/no) | Occupation in pregnancy and 3 months prior | ||
| Kristensen 1997 [48] | Norway 1967–1991 | Birth register (270:253,498) | Birth record linked to agricultural census | YES | Farming parents (yes/no) Use of tractor spraying equipment, tractor spraying + grain cultivation |
Occupation at time of pregnancy and birth | Farming parents (yes/no) Use of tractor spraying equipment, tractor spraying + grain cultivation |
Occupation at time of pregnancy and birth |
Olshan et al. adjusted for parental ages, race, and outcome of previous pregnancies. Garcia et al. matched cases and controls according to hospital and approximate date of birth. Carbone et al. adjusted for birth weight, parity, mother’s age, mother’s education, TTP, condom use, mother’s gynecological diseases, father’s urogenital diseases, use of antiabortion drugs, mother’s alcohol use during pregnancy, and other parent’s exposure to pesticides. Weidner et al. adjusted for year of birth and birth weight. Kristensen et al. adjusted for year of birth, maternal age, geographical region, and parental consanguinity.
Exposure to pesticides was classified as: improbable or probable.
Agricultural work was classified as: no, in related occupations, work in the field, or work in a greenhouse.
Exposure to pesticides was classified as: improbable, probable or highly probable.