Table 3.

Relative risks (RR) for neck pain alone (NP), low back pain alone (LBP), and concomitant neck and low back pain (NLBP) in 1999, and in 2011 compared to the reference year 1991

	RR (95% CI) for pain in 1999 compared to 1991 (RR 1.00)	RR (95% CI) for pain in 2011 compared to 1991 (RR 1.00)
NP alone
Boys
12-14	1.30 (0.97 to 1.75)	1.25 (0.89 to 1.76)
16-18	1.32 (1.07 to 1.63)	1.52 (1.18 to 1.94)
Girls
12-14	1.64 (1.38 to 1.94)	1.66 (1.38 to 2.00)
16-18	1.29 (1.17 to 1.42)	1.30 (1.17 to 1.45)
LBP alone
Boys
12-14	0.76 (0.50 to 1.14)	1.14 (0.75 to 1.75)
16-18	0.85 (0.65 to 1.11)	1.27 (0.94 to 1.72)
Girls
12-14	0.87 (0.57 to 1.33)	1.12 (0.72 to 1.75)
16-18	0.77 (0.58 to 1.03)	0.92 (0.67 to 1.27)
NLBP
Boys
12-14	1.77 (1.09 to 2.87)	2.37 (1.42 to 3.95)
16-18	1.36 (1.03 to 1.79)	2.33 (1.75 to 3.12)
Girls
12-14	2.07 (1.38 to 3.10)	3.71 (2.50 to 5.50)
16-18	1.46 (1.21 to 1.76)	2.29 (1.90 to 2.76)

Calculations are based on the prevalences presented in Table 2.