Summary of findings for the main comparison. Cycled light (CL) compared with irregular dimmed light or near darkness (ND) for preterm or low birth weight infants.

Cycled light (CL) compared with irregular dimmed light or near darkness (ND) for preterm or low birth weight infants
Patient or population: preterm or low birth weight infants undergoing hospital care Settings: hospital Intervention: cycled light (CL) Comparison: irregular dimmed light or near darkness (ND)
Outcomes	Illustrative comparative risks* (95% CI)		Number of participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Dimmed light or near darkness (ND)	Cycled light
Weight (g) at 4 months	Mean weight in control group (ND) was 6264 g	Mean weight in the CL group was non‐significantly higher than in the control group (MD 181.0 g, 95% CI ‐484.0 to 846)	40 (1)	⊕⊕⊝⊝ Low	Bias: inevitable high risk of bias as the study could not be blinded Consistency: As only 1 study reported on this outcome, inconsistency was not a concern Precision: low precision as total sample size was small and CI was wide Indirectness: Study was conducted in the target population (no concerns about indirectness)
Length of stay (days) (CL from 32 weeks' PMA)	Mean length of stay ranged across control groups (ND) from 54 to 86 days	WM length of stay for CL groups was significantly shorter than for control groups (WMD ‐12.7 days, 95% CI ‐23.0 to ‐2.3)	77 (2)	⊕⊕⊝⊝ Low	Bias: inevitable high risk of bias as studies could not be blinded Consistency: Findings of the 2 studies were consistent with I2 = 0% Precision: low precision as total sample size was small and CIs were wide Indirectness: Studies were conducted in the target population (no concerns about indirectness)
*The basis for the assumed risk was as follows: 'The mean [outcome] ranged across control groups from [value][measure].' Corresponding risk was as follows: 'The mean [outcome] in the intervention groups was [value] [lower/higher] [(value to value lower/higher)] with 95% CI' CI: confidence interval; RR: risk ratio; WM: weighted mean; WMD: weighted mean difference
GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate Very low quality: We are very uncertain about the estimate