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12-Hour Eating Window Before 8 PM Reduces Blood Pressure in Children Over 12 Months
A cluster-randomized trial found that a 12-hour time-restricted eating window with the last meal completed before 8 PM was associated with a systolic blood pressure reduction of approximately 7 mmHg over 12 months in children and adolescents with elevated blood pressure (-7.03 mmHg, 95% CI -10.77 to -3.29 mmHg). The result is promising but should be interpreted with caution given substantial participant dropout and retrospective trial registration.
What Was Studied
This trial investigated whether time-restricted eating (TRE) — limiting food intake to a defined daily window — could safely and effectively lower blood pressure in children and adolescents already presenting with elevated readings. Pediatric hypertension is an underrecognized risk factor for cardiovascular disease later in life, and non-pharmacological dietary strategies represent an appealing first-line approach in young populations.
How It Was Studied
Researchers conducted a 12-month, three-arm cluster-randomized controlled trial across two schools in China, using school classes (91 total) as the unit of randomization rather than individual students, which controls for social contamination within classrooms. A total of 192 children and adolescents with elevated blood pressure were enrolled and distributed equally across three groups of 64: TREa, which imposed a 12-hour eating window with a strict last-meal cutoff before 8:00 PM; TREb, which required a 12-hour window but without a fixed evening endpoint; and a control group that received no dietary timing instruction. Outcomes were analyzed under an intention-to-treat framework using mixed-effects models that accounted for the clustered study design, with multiple imputation applied as a sensitivity analysis to address missing data from the substantial dropout observed at both the 6-month and 12-month follow-up points.
What Was Observed
- The TREa group — with its fixed pre-8 PM cutoff — achieved a mean systolic blood pressure reduction of approximately 7 mmHg over 12 months (-7.03 mmHg, 95% CI -10.77 to -3.29 mmHg), a magnitude considered clinically meaningful in pediatric hypertension management. This was the largest reduction observed across the three arms.
- Both TRE groups showed statistically significant blood pressure reductions compared to controls at 12 months, suggesting that the eating-window concept itself carries benefit, but the addition of a fixed evening meal deadline in TREa appears to amplify the effect beyond what unrestricted-timing TREb achieved.
- Retention across the trial was notably low: only about 65% of participants completed 6-month assessments and roughly 59% reached the 12-month endpoint, representing loss-to-follow-up rates of 34.9% and 40.6% respectively — a factor that limits confidence in the precision of the estimates, even after sensitivity analyses.
Why This Matters
Time-restricted eating has attracted substantial research interest in adults, but evidence in pediatric populations remains sparse. This trial offers some of the first controlled longitudinal data suggesting that dietary timing — specifically curtailing late-evening eating — may influence blood pressure regulation in children through mechanisms potentially involving circadian rhythm alignment and metabolic homeostasis. If replicated in larger and more rigorously retained samples, these findings could inform school-based public health strategies targeting early cardiovascular risk.
How to Read This Result
The combination of high attrition (over 40% by 12 months), retrospective trial registration, and a two-school study design limits the generalizability and robustness of these findings, and independent replication in more diverse populations is needed before firm conclusions can be drawn.
Limitations
The authors explicitly note that the cluster design and substantial attrition should be factored into any interpretation of the results. Follow-up completion reached only 59.4% at the 12-month primary endpoint, raising concerns about selection bias despite the use of multiple imputation. The trial was also retrospectively registered, which introduces uncertainty about whether the reported outcomes were fully pre-specified.