Table 1.

Characteristics of the sample population.

	Control (n = 71,076)		DM (n = 35,538)		P a
	n	%	n	%
Age, years (mean ± SD)	51.06 ± 11.01		51.07 ± 11.00		0.926
0–9	84	0.12	41	0.12	0.998
10–19	275	0.39	133	0.37
20–29	1907	2.68	946	2.66
30–39	7907	11.12	3931	11.06
40–49	21,672	30.49	10,879	30.61
50–59	26,274	36.97	13,094	36.85
60–69	9852	13.86	4967	13.98
≥ 70	3105	4.37	1547	4.35
Sex
Female	28,044	39.46	14,022	39.46	1.000
Male	43,032	60.54	21,516	60.54
Charlson’s comorbidity index
0	40,043	56.34	16,130	45.39	< 0.001
1	16,769	23.59	9346	26.30
2–3	7840	11.03	5267	14.82
≥ 4	6424	9.04	4795	13.49
Comorbidities
HF	1187	1.67	1237	3.48	< 0.001
AMI	316	0.44	325	0.91	< 0.001
Stroke	3482	4.90	2804	7.89	< 0.001
Ischemic heart disease	6684	9.40	5687	16.00	< 0.001
Angina	2469	3.47	2018	5.68	< 0.001
Peripheral vascular disease	2184	3.07	1666	4.69	< 0.001
Hypertension	14,166	19.93	14,902	41.93	< 0.001
Hyperlipidemia	9553	13.44	9543	26.85	< 0.001
Renal failure	2935	4.13	2299	6.47	< 0.001
Chronic liver disease	11,892	16.73	9597	27.00	< 0.001
COPD	8610	12.11	5264	14.81	< 0.001
Cataract	10,260	14.44	9219	25.94	< 0.001
Level of urbanization
Urban	56,117	78.95	27,760	78.11	0.002
Suburban	11,126	15.65	5711	16.07
Rural	3833	5.39	2067	5.82
Monthly income (NT$)
0	2761	3.88	1481	4.17	< 0.001
1–21,000	14,455	20.34	8048	22.65
21,000–33,300	22,092	31.08	11,838	33.31
≥ 33,301	31,768	44.70	14,171	39.88
Residence
North	40,662	57.21	19,240	54.14	< 0.001
Central	14,146	19.90	7543	21.23
South	14,911	20.98	7952	22.38
East and other	1357	1.91	803	2.26
New-onset myopia
Low myopia	1189	1.67	898	2.53	< 0.001
High myopia	193	0.27	97	0.27	0.967
Low/high myopia/astigmatism	1419	2.00	1058	2.98	< 0.001

^aCategorical variables: Chi-squared test; continuous variables: T test.