Table 2.

Age-adjusted Incidence Rate Ratios (IRR) with 95% Confidence Intervals (CI) for tonsillectomy and/or adenoidectomy (A/T) among children aged 2–9 years.

	IRR	(95% CI)
Males vs females	1.29	(1.25–1.33)
Non-Italian vs Italian children	0.57	(0.53–0.61)
A/T rates (×1000) in each LHU, age class 10–40 yrs	1.51	(1.22–1.86)

LHU-level variance = 0.048.

Random-intercept Poisson regression; clustering variable = Local Health Unit (LHU).