Epidemiology of spinal pain in children: a study within the Danish National Birth Cohort

doi:10.1007/s00431-019-03326-7

Table 4
Relative risk ratio (RRR) of overall spinal pain according to potential risk factors among the 46,726 children participated in the 11-year follow-up in the Danish National Birth Cohort
Characteristics Overall spinal pain
Model^ab Model 2^ac
Moderate pain
RRR (95% CI) Severe pain
RRR (95% CI) Moderate pain
RRR (95% CI) Severe pain
RRR (95% CI)
Sex, age
Boys, 11 years Ref. Ref. Ref. Ref.
Boys, 12 years 1.12 (1.03–1.21) 1.16 (1.03–1.31) 1.12 (1.03–1.21) 1.15 (1.02–1.30)
Boys, 13+ years 1.41 (1.18–1.69) 1.29 (0.98–1.70) 1.41 (1.17–1.69) 1.26 (0.96–1.66)
Girls, 11 years 1.15 (1.10–1.20) 1.46 (1.37–1.56) 1.14 (1.09–1.19) 1.44 (1.35–1.54)
Girls, 12 years 1.41 (1.31–1.53) 2.39 (2.16–2.64) 1.41 (1.30–1.52) 2.34 (2.12–2.59)
Girls, 13+ years 1.49 (1.23–1.80) 3.47 (2.83–4.26) 1.48(1.23–1.79) 3.40 (2.77–4.18)
Sibling position
Biological full siblings Ref. Ref. Ref. Ref.
Biological only child 1.18 (1.10–1.25) 1.35 (1.24–1.47) 1.12 (1.05–1.20) 1.18 (1.08–1.30)
Family type
Child lives with both parents Ref. Ref. Ref. Ref.
Child not living with (both) parents^d 1.25 (1.19–1.31) 1.57 (1.47–1.68) 1.18 (1.12–1.25) 1.39 (1.29–1.50)
Maternal educational level
High Ref. Ref. Ref. Ref.
Medium 1.02 (0.98–1.07) 1.18 (1.13–1.27) 0.99 (0.94–1.03) 1.11 (1.05–1.19)
Low 1.08 (1.00–1.20) 1.62 (1.45–1.82) 1.01 (0.92–1.11) 1.37 (1.21–1.55)
Equivalised household income
4th quartile (highest) Ref. Ref. Ref. Ref.
3rd quartile 1.06 (1.01–1.12) 1.10 (1.02–1.18) 1.05 (1.00–1.11) 1.06 (0.98–1.14)
2nd quartile 1.11 (1.05–1.17) 1.23 (1.14–1.33) 1.07 (1.01–1.13) 1.09 (1.00–1.18)
1st quartile (lowest) 1.19 (1.10–1.27) 1.55 (1.46–1.70) 1.10 (1.02–1.18) 1.23 (1.11–1.36)
Maternal age at childbirth
≤ 25 years Ref. Ref. Ref. Ref.
26–30 years 0.92 (0.86–0.98) 0.84 (0.77–0.92) 0.96 (0.89–1.02) 0.95 (0.86–1.04)
31–35 years 0.91 (0.85–0.98) 0.81 (0.74–0.89) 0.95 (0.89–1.02) 0.91 (0.83–1.01)
> 35 years 0.87 (0.80–0.95) 0.78 (0.69–0.88) 0.90 (0.83–0.98) 0.87 (0.77–0.98)
^aReference category: not having reported moderate or severe spinal pain (no pain)
^bCrude model
^cAdjusted for additional variables in the model, as well as the interaction between child’s age and sex (P < 0.001)
^dParents not living together due to divorce, separation, they never lived together, or only one parent alive

Characteristics	Overall spinal pain
	Model^ab		Model 2^ac
	Moderate pain RRR (95% CI)	Severe pain RRR (95% CI)	Moderate pain RRR (95% CI)	Severe pain RRR (95% CI)
Sex, age
Boys, 11 years	Ref.	Ref.	Ref.	Ref.
Boys, 12 years	1.12 (1.03–1.21)	1.16 (1.03–1.31)	1.12 (1.03–1.21)	1.15 (1.02–1.30)
Boys, 13+ years	1.41 (1.18–1.69)	1.29 (0.98–1.70)	1.41 (1.17–1.69)	1.26 (0.96–1.66)
Girls, 11 years	1.15 (1.10–1.20)	1.46 (1.37–1.56)	1.14 (1.09–1.19)	1.44 (1.35–1.54)
Girls, 12 years	1.41 (1.31–1.53)	2.39 (2.16–2.64)	1.41 (1.30–1.52)	2.34 (2.12–2.59)
Girls, 13+ years	1.49 (1.23–1.80)	3.47 (2.83–4.26)	1.48(1.23–1.79)	3.40 (2.77–4.18)
Sibling position
Biological full siblings	Ref.	Ref.	Ref.	Ref.
Biological only child	1.18 (1.10–1.25)	1.35 (1.24–1.47)	1.12 (1.05–1.20)	1.18 (1.08–1.30)
Family type
Child lives with both parents	Ref.	Ref.	Ref.	Ref.
Child not living with (both) parents^d	1.25 (1.19–1.31)	1.57 (1.47–1.68)	1.18 (1.12–1.25)	1.39 (1.29–1.50)
Maternal educational level
High	Ref.	Ref.	Ref.	Ref.
Medium	1.02 (0.98–1.07)	1.18 (1.13–1.27)	0.99 (0.94–1.03)	1.11 (1.05–1.19)
Low	1.08 (1.00–1.20)	1.62 (1.45–1.82)	1.01 (0.92–1.11)	1.37 (1.21–1.55)
Equivalised household income
4th quartile (highest)	Ref.	Ref.	Ref.	Ref.
3rd quartile	1.06 (1.01–1.12)	1.10 (1.02–1.18)	1.05 (1.00–1.11)	1.06 (0.98–1.14)
2nd quartile	1.11 (1.05–1.17)	1.23 (1.14–1.33)	1.07 (1.01–1.13)	1.09 (1.00–1.18)
1st quartile (lowest)	1.19 (1.10–1.27)	1.55 (1.46–1.70)	1.10 (1.02–1.18)	1.23 (1.11–1.36)
Maternal age at childbirth
≤ 25 years	Ref.	Ref.	Ref.	Ref.
26–30 years	0.92 (0.86–0.98)	0.84 (0.77–0.92)	0.96 (0.89–1.02)	0.95 (0.86–1.04)
31–35 years	0.91 (0.85–0.98)	0.81 (0.74–0.89)	0.95 (0.89–1.02)	0.91 (0.83–1.01)
> 35 years	0.87 (0.80–0.95)	0.78 (0.69–0.88)	0.90 (0.83–0.98)	0.87 (0.77–0.98)