Table 2

Mean hearing threshold shifts in different ages compared with first audiometric examination (at 18 years), measured at 0.5, 1, 2, 4 and 8 kHz

	Difference mean	SE	95% CI		p Value
	Difference mean	SE	Lower bound	Upper bound	p Value
0.5 kHz
30	−3.742	0.533	−4.789	−2.697	***
35	−3.181	0.535	−4.229	−2.132	***
40	−2.832	0.537	−3.886	−1.779	***
45	−2.806	0.629	−4.039	−1.573	***
50	−2.904	0.911	−4.691	−1.118	***
1 kHz
30	−2.139	0.547	−3.221	−1.067	*
35	−1.316	0.548	−2.391	−0.241	*
40	−0.640	0.551	−1.720	0.440	NS
45	0.245	0.644	−1.018	1.509	NS
50	−0.038	0.934	−1.869	1.793	NS
2 kHz
30	−0.029	0.585	−1.176	1.118	NS
35	0.981	0.587	−0.170	2.131	NS
40	1.357	0.589	0.201	2.512	NS
45	1.766	0.690	0.413	3.118	*
50	2.288	0.999	0.328	4.248	*
4 kHz
30	2.973	0.855	1.296	4.650	**
35	5.595	0.858	3.913	7.277	***
40	8.732	0.862	7.041	10.423	***
45	12.076	1.008	10.099	14.053	***
50	15.325	1.461	12.460	18.190	***
8 kHz
30	−0.298	0.941	−2.144	1.547	NS
35	1.389	0.943	−0.462	3.239	NS
40	2.906	0.948	1.047	4.765	*
45	5.055	1.109	2.880	7.230	***
50	7.977	1.607	4.825	11.129	***

*p<0.05, **p<0.01 and ***p<0.001.
NS, not significant.