TABLE II.

Incidence Rates for All Injuries, Strains & Sprains, and Back Injuries by Socioeconomic Status (SES): 1468 Massachusetts Hospitals Workers, 2003-2005

SES	SES label	n workers	All injuries rate per 100 FTEs*(95%CI)	Strain & sprain injuries rate per100 FTEs*(95%CI)	Back injuries rate per 100 FTEs*(95%CI)
6	Administrators	55	2.6 (.97–6.9)	0.0 (no cases)	0.0 (no cases)
5	Professionals	227	8.8 (6.6–11.7)	2.7 (1.6–4.5)	1.3 (.64–2.8)
4	Nurses	358	18.5 (15.7–21.8)	4.6 (3.4–6.4)	2.1 (1.3–3.4)
3	Semi-professionals	276	12.7 (10.1–15.8)	4.1 (2.8–6.1)	1.9 (1.1–3.3)
2	Skilled	445	8.1 (6.4–10.2)	1.4 (.77–2.4)	.45 (.17–1.2)
1	Semi-skilled	107	16.6 (12.1–22.8)	3.5 (1.7–7.0)	2.2 (.91–5.2)
Totals	All SES categories	1468	11.9 (10.8–13.2)	3.0 (2.4–3.6)	1.4 (1.0–1.9)

Full time employee equivalence (FTEs) (scheduled weekly work hours for each employee/40 hours) × number of years employed during followup.