Prevalence of childhood hearing impairment in the County of Stockholm – a 40-year perspective from Sweden and other high-income countries

Figures & data

Figure 1. There is a clear trend of increasing prevalence rates across age, with significant differences across all types of HI. However, in older children, this increase in prevalence appears to be dominated by unilateral and mild HI.

Table 1. Prevalence data from all children and adolescents, 0–18 years old, registered with hearing impairment in the database Audiohab, living in the Stockholm County in December 2017.

Age in years 2017	Registered Audiohab, All	Preval-ence/1000	Audiohab bilateral >40 dB	Preva-lence/1000	Audiohab bilateral <40 dB	Preval-ence/1000	Audiohab unilateral >40 dB		Preval-ence/1000	Audiohab bilateral >60 dB	Preval-ence/1000	Total population 2017
0	24	0.97	13	0.53	5	0.20	6	0.24		7	0.28	24,740
1	35	1.17	20	0.67	6	0.20	9	0.30		9	0.30	29,849
2	50	1.68	27	0.91	8	0.27	15	0.50		12	0.40	29,670
3	61	2.04	34	1.10	9	0.30	17	0.57		13	0.44	29,873
4	80	2.69	43	1.45	15	0.50	22	0.74		26	0.88	29,680
1–4	226	1.89	124	1.04	38	0.32	63	0.53		60	0.50	119,072
5	79	2.70	38	1.30	19	0.65	21	0.72		17	0.62	29,244
6	92	3.16	43	1.48	25	0.86	26	0.89		14	0.48	29,116
7	105	3.46	50	1.65	28	0.92	27	0.89		17	0.56	30,347
8	119	4.08	52	1.78	30	1.03	37	1.26		26	0.89	29,258
9	101	3.47	42	1.44	33	1.13	26	0.89		18	0.62	29,094
5–9	496	3.37	225	1.53	135	0.92	137	0.93		92	0.63	147,059
10	119	4.17	41	1.44	34	1.19	43	1.51		18	0.63	28,528
11	141	5.00	47	1.67	38	1.35	55	1.96		21	0.75	28,108
12	128	4.70	34	1.26	47	1.74	47	1.74		19	0.70	27,071
13	146	5.42	56	2.08	39	1.45	49	1.82		25	0.93	26,930
14	109	4.17	40	1.53	27	1.03	42	1.61		13	0.50	26,155
10–14	643	4.70	218	1.59	185	1.35	236	1.73		96	0.70	136,792
15	119	4.70	45	1.78	28	1.11	45	1.78		29	1.15	25,311
16	129	5.33	51	2.10	37	1.53	40	1.65		25	1.00	24,191
17	150	6.22	55	2.28	50	2.07	45	1.87		25	1.00	24,103
18	124	5.23	57	2.40	33	1.39	34	1.44		23	1.00	23,689
15–18	522	5.37	208	2.14	148	1.52	164	1.69		102	1.00	97,294
All	1911	3.64	788	1.50	511	0.97	606	1.15		357	0.68	524,957

Prevalence based on Audiohab register data and the total population of each age group as reported from Statistics Sweden (SCB). Data are also collected in four groups (in italics); 1–4, 5–9, 10–14 and 15–18 years of age.

Table 2. Chi-square (χ²) analyses comparing prevalence of HI between age-groups.

Age group comparison (years)	All HI >25 dB HL		Bilateral >40 dB HL		Unilateral >40 dB HL		Bilateral <40 dB HL
	χ^2	p-value	χ^2	p-value	χ^2	p-value	χ^2	p-value
1–4
5–9	52.9	<0.001*	12.1	<0.001†	14.2	<0.001†	36.4	<0.001†
10–14	147.7	<0.001*	14.7	<0.001†	71.7	<0.001†	78.3	<0.001†
15–19	199.3	<0.001*	46.2	<0.001†	72.8	<0.001†	94.8	<0.001†
5–9
10–14	31.3	<0.001*	0.20	0.66	34.1	<0.001†	11.9	<0.001†
15–18	64.0	<0.001*	6.8	0.009	30.2	<0.001†	20.9	<0.001†
10–14
15–18	7.8	0.005*	11.4	<0.001†	0.008	0.93	1.84	0.17

Significant comparisons are marked to the Bonferonni-corrected α-values of *0.008 and †0.003.

Table 3. Comparison of prevalence rate from register-based reference studies of childhood hearing loss and current study data from Stockholm County.

Reference study	Location	Cohort details			Definition of hearing loss (dB HL, BE)	Prevalence rate per 1000
		Population	Birth years	Age in years		Reference study	Adjusted to ≥40 dB HL PTA4 BE	Current study (age matched)	χ^2 (p-value)
Kankkunen Acta Otolaryngol, 1982	Gothenburg City, Sweden	36,855	1970–1975	0–6	≥41 PTA3	1.07	1.10	1.07	0.06 (0.81)
Parving Int J Ped Otolaryngol, 1983	Copenhagen County, Denmark	82,265	1970–1979	2–12	≥35 PTA3	1.4	1.35	1.41	0.17 (0.68)
Hirsch Scand Audiol, 1988	Stockholm County, Sweden	89,643	1976–1980	6–7	≥50 PTA3	1.0	1.39	1.56	0.70 (0.40)
Sehlin et al. Scand Audiol, 1990	Västerbotten County, Sweden	63,463	1964–1983	0–20	≥40 PTA3	1.81	1.86	1.50**	4.82 (0.03^†)
Davis & Wood British J Audiol, 1992	Nottingham, U.K.	29,317	1983–1986	3–6	≥50 PTA4	1.40	1.64	1.34	1.48 (0.22)
Drews C et al. Public Health Briefs, 1994	Atlanta, USA	89,534	1975–1977	10	≥40 PTA3	1.12	1.15	1.44	1.46 (0.23)
Fortnum & Davis British J Audiol, 1997	Trent Region, U.K.	366,480	1985–1990	4–9	≥40 PTA4	1.33		1.52	3.01 (0.08)
Vartiainen et al, Int J Ped Otolaryngol 1997	Eastern Finland	46,240	1974–87	0–8	≥41 PTA4	1.12		1.21	0.27 (0.61)
Mäki Torkko et al. Scan Audiol, 1998 (1)	Northern Finland	108,461*	1973–1982	0–14	≥40 PTA4	1.3		1.35	0.17 (0.68)
Mäki Torkko et al. Scan Audiol, 1998 (2)	Northern Finland	101,818*	1983–1992	0–8	≥40 PTA4	1.1		1.21	0.82 (0.37)
Van Naarden et al. Paediatrics 1999	Atlanta, USA	790,200	1981–1990	3–10	≥40 PTA3	1.1	1.13	1.46	15.9 (<0.001^†)
Uus & Davis, Audiology 2000	Estonia	144,186	1985–1990	8–13	≥40 PTA4	1.72		1.61	0.57 (0.45)
Fortnum et al. British J Audiol, 2001 (1)	U.K.	Unknown	1995	3	≥41 PTA4	0.91		1.1	CND
Fortnum et al. British J Audiol, 2001 (2)	U.K.	4,644,400	1985–1990	8–13	≥41 PTA4	1.63		1.61	0.04 (0.85)
Nekahm et al. Scand Audiol, 2001	Tyrol region, Austria	124,809*	1980–1994	6–18	≥40 PTA4	1.32		1.74	9.94 (0.002^†)
Russ et al. Int J Audiol, 2003	Victoria, Australia	64,116	1993	6	≥41 PTA3	1.12	1.15	1.48	1.66 (0.20)
Ching et al. Aust New Zeal J Audiol, 2006 (1)	Australia, all 5 states	245,192*	2003	3	≥40 PTA3	1.04	1.07	1.1	0.11 (0.74)
Ching et al. Aust New Zeal J Audiol, 2006 (2)	Australia, all 5 states	Unknown	1990–2003	9–16	≥40 PTA3	1.57	1.62	1.65	CND
Dietz et al. Int J Ped Otolaryngol, 2009	Kuopio Province, Finland	43,711	1988–2002	0–7	≥40 PTA4	1.24		1.14	0.26 (0.61)
Watkin & Baldwin Arch Dis Child, 2011	Waltham Forest, U.K.	35,668	1992–2002	5	≥40 PTA4	1.51		1.30	0.52 (0.47)
Häkli et al. Int J Ped Otolaryngol, 2014	Northern Finland	91,835	1993–2002	0–10	≥40 PTA4	1.1		1.26	0.26 (0.61)

Data from 18 studies presented in the table describe the prevalence of moderate to profound hearing loss in children and youth. These references studies are from high-income or European countries, similar to Stockholm region, and they include data from children born from 1964 to 2003. All studies are register based. The existing data in these studies are compared with current age-matched data from Stockholm region. Because the definition of hearing loss in previous studies often differs from present day conventions, these data have been adjusted to match the definition used by the bulk of modern studies (≥40 dB HL PTA4 in the better ear [BE]). The conversion from ≥50 to ≥40 dB HL was achieved by adding half the number of children with a hearing loss <50 dB to the total number of children with hearing loss ≥50 dB HL. Similarly, the adjustment from ≥35 to ≥40 dB HL was achieved by removing half the children with a hearing loss between 35–44 dB HL from the total number. The quantification of a moderate to profound hearing loss in the Stockholm registry is ≥41 dB HL PTA4 BE. Despite the differences in the minimum threshold, prevalence rates from previous studies were not adjusted from ≥40 to ≥41 dB, to avoid insertion of additional error to the data. For studies using PTA3, 3% was added to the prevalence rate corresponding to the difference in hearing level between PTA3 (0.5, 1 and 2 kHz) and PTA4 (0.5, 1, 2 and 4 kHz), based on Pittman and Stelmachowicz (2003) study of hearing levels in children at 0.5, 1, 2 and 4 kHz.

Chi-square (χ²) analyses were performed in R i386 version 3.5.2 (R Core Team 2018). The results showed that for the majority of comparisons, differences were not significant between existing prevalence rates and age-matched data from the current study. Significant differences (p < 0.05) were found for three studies.

BE: better ear, HL: hearing level, PTA: pure tone average, CND: could not determine

^† Significant difference (p < 0.05). *Population calculated from number of children with hearing loss and prevalence. **Age group 0–18 years, current study.

Kankkunen, A. 1982. “Preschool Children with Impaired Hearing.” Acta Oto-Laryngologica 94 (391): 1–99. doi:10.3109/00016488209108896.

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Pittman, A. L., and P. G. Stelmachowicz. 2003. “Hearing Loss in Children and Adults: Audiometric Configuration, Asymmetry, and Progression.” Ear and Hearing 24 (3): 198–205. doi:10.1097/01.AUD.0000069226.22983.80.

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R Core Team. 2018. R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing.

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