Table 4. Synthesis of results, stratified by cut-off points and screen equipment evaluated (n=9).

Cut-off points	Type of screen and results
≥2 hours per week	Computer: week days: RR=1.5 (95%CI 1.0–2.1) 26
	Computer: weekends: RR=1.8 (95%CI 1.4–2.4) 26
≥2 hours per day	Computer: Non-adjusted RP=1.2 (95%CI 0.9–1.8) 23 Computer and television: Adjusted OR=0.3 (95%CI 0.1–1.4) * 24 ; Adjusted OR=3.0 (95%CI 0.7–13.9) † 24 Television: Adjusted OR=1.9 (95%CI 1.3–2.7) 19 ; Non-adjusted RP=1.0 (95%CI 0.8–1.2) 22 ; Non-adjusted RP=0.9 (95%CI 0.7–1.2) 23 Cell phone, computer, tablet, television and video games: no risk associations 21 Use of more than one screen device: girls: no risk associations 21 ; boys: Adjusted OR=0.3 (95%CI 0.1–0.9) 21
≥3 hours per day	Cell phone: Adjusted RP=1.4 (95%CI 1.1–1.7) 18 Tablet: Adjusted RP=1.5 (95%CI 1.2–1.8) 18 Television: Adjusted RP=1.2 (95%CI 1.0–1.4)18; Adjusted OR=1.5 (95%CI 1.0–2.3) ‡ 20
≥4 hours per day	Computer/games: Adjusted OR=1.3 (95%CI 1.0–1.8) 25
≥5 hours per day	Computer: Non-adjusted RP=1.2 (95%CI 0.8–1.8) 23 Television: Non-adjusted RP=0.7 (95%CI 0.5–1.2) 23

^*low back pain at the time of study;

^†low back pain at some point in life;

^‡>3 times a week and 3 hours a day; 95%CI: 95% confidence interval; OR: Odds Ratio (odds ratio); PR: prevalence ratio; RR: relative risk.