Table 2.

Hazard ratios (HRs) for maternal occupational noise exposure during pregnancy and hearing dysfunction in 1,422,333 children (1,320,195 children in the adjusted analyses).

Occupational noise exposure (dBA)a	Hearing dysfunction, allb			Sensorineural hearing lossc			Tinnitusd
	n cases (crude/adjusted)	Crudee[HR (95% CI)]	Adjustedf [HR (95% CI)]	n cases (crude/adjusted)	Crudee [HR (95% CI)]	Adjustedf [HR (95% CI)]	n cases (crude/adjusted)	Crudee [HR (95% CI)]	Adjustedf [HR (95% CI)]
< 75 dBA	9,813/9,001	1.00	1.00	6,688/6,176	1.00	1.00	2,548/2,285	1.00	1.00
75–84 dBA	2,790/2,545	0.96 (0.92, 1.00)	1.05 (1.00, 1.10)	1,962/1782	1.01 (0.96, 1.06)	1.08 (1.03, 1.15)	706/645	0.89 (0.82, 0.97)	0.99 (0.90, 1.08)
≥ 85 dBA	65/60	1.20 (0.94, 1.53)	1.27 (0.99, 1.64)	46/42	1.26 (0.94, 1.68)	1.26 (0.93, 1.70)	16/14	1.10 (0.67, 1.80)	1.25 (0.74, 2.12)
aOccupational noise exposure estimated through a job–exposure matrix based on measurements at several work sites, classifying the mother’s occupation registered at the beginning of the pregnancy (gestational week 10) into one of three noise categories. bHearing dysfunction all selected diagnoses, includes other diseases of inner ear (ICD-10 codes H83.3, H83.8), sensorineural hearing loss and sensorineural mixed with conductive hearing loss (H90.3-7), other hearing loss (H91.0, H91.2-3, H91.8), and other disorders of ear, not elsewhere classified (H93.1, H93.2). cSensorineural hearing loss includes sensorineural hearing loss and mixed conductive and sensorineural ICD-10: H90.3-7. dTinnitus includes ICD10: H93.1. eCrude analyses were restricted to all single births between 1986 and 2008 and excluding mothers in nonworking categories (students, house wives, unemployed, refugees). fAnalyses adjusted for mother’s age, smoking, education, family structure, and nationality and child’s sex, birth year, and parity. Including all single births between 1986 and 2008 and excluding mothers in nonworking categories (students, housewives, refugees).