Table 3.

Migrants to the Netherlands v. native-born controls (=Reference population): Rates for migrants (number/10 000 person-years) and Incidence Rate Ratios (IRRs) of Incident Diagnosis Treatment Combinations (IDTCs, 2011–2016), by number of years since arrival, age, and region of origin

Age at arrival*	10–20 year	IRR [95%–CI]	20–40 year	IRR [95%–CI]	40–60 year	IRR [95%–CI]
Region of origin	Rate (/10 000 person-years)		Rate (/10 000 person-years)		Rate (/10 000 person-years)
Years since arrival
Non-Western migrants: other 1	9.9	1.63 [0.94–2.85]	13.7	0.50 [0.41–0.61]	25.2	0.64 [0.45–0.90]
2–3	7.4	2.18 [1.30–3.66]	8.4	1.13 [0.93–1.38]	14.5	2.84 [1.81–4.46]
4–6	8.0	1.45 [0.73–2.87]	6.9	1.35 [0.95–1.91]	10.7	2.91 [1.29–6.56]
Year 1–6: χ2, df, p value		1.02, 2, 0.601		42.2, 2, <0.001		31.4, 2, 0.001
Non-Western migrants: Sub-Saharan Africa 1	32.9	6.09 [2.93–12.64]	62.4	2.32 [1.78–3.04]	48.9	2.03 [0.99–4.15]
2–3	17.8	8.27 [3.38–20.22]	23.4	3.03 [2.12–4.34]	13.0	2.50 [0.84–7.45]
4–6	16.8	10.27 [2.25–46.86]	19.0	2.92 [1.57–5.43]	7.4	2.08 [0.29–14.75]
Year 1–6: χ2, df, p value		0.50, 2, 0.778		1.52, 2, 0.468		0.10, 2, 0.950
Western migrants: Eastern Europe 1	8.7	1.41 [0.61–3.26]	14.3	0.48 [0.39–0.59]	16.9	0.39 [0.25–0.61]
2–3	3.2	0.62 [0.27–1.44]	8.3	1.11 [0.90–1.38]	8.7	1.08 [0.67–1.76]
4–6	6.3	1.16 [0.43–3.14]	7.5	1.42 [0.99–2.04]	10.5	3.88 [1.55–9.73]
Year 1–6: χ2, df, p value		1.98, 2, 0.371		41.9, 2, <0.001		23.0, 2, <0.001
Western migrants: other 1	1.0	0.13 [0.02–0.97]	7.1	0.26 [0.19–0.35]	12.1	0.30 [0.17–0.53]
2–3	2.8	0.46 [0.21–0.98]	4.9	0.64 [0.49–0.84]	6.5	0.89 [0.50–1.58]
4–6	5.3	1.03 [0.36–2.98]	3.8	0.92 [0.53–1.59]	4.1	1.45 [0.41–5.13]
Year 1–6: χ2, df, p value		3.54, 2, 0.171		26.69, 2, <0.001		9.160, 2, 0.010

*Tables 2 and 3: Age of arrival was categorised in these broad age groups. The matching of cases to controls was done in a more fine-grained way by categorising calendar year of birth in 5-year groups (see Methods).