Dietary indices underpinning front-of-pack nutrition labels and health outcomes: a systematic review and meta-analysis of prospective cohort studies

Background
Nutrient profiling systems are increasingly used to characterize the healthfulness of foods for front-of-package (FOP) labeling, which have been proposed as an effective public health strategy to help people make healthier food choices.
Objective
This study aimed to review available evidence from cohort studies that evaluated the association of dietary indices underpinning FOP nutrition labels with all-cause mortality and incidence of cardiovascular diseases (CVDs) or cancer.
Methods
PubMed, Web of Science, and Scopus were systematically searched up to October 2023. We included articles if they were prospective cohort studies, if the exposure was any dietary index underpinning FOP nutrition labels [e.g., the modified Food Standard Agency-Nutrient Profiling System (FSAm-NPS) and the Health Star Rating System], and if outcomes were all-cause mortality or incidence of or mortality due to CVD and cancer. Random-effects models were used to calculate the pooled hazard ratios (HRs) and 95% CIs.
Results
We identified 11 records (7 unique prospective studies), which were included in the systematic review. The meta-analysis comprised 8 studies analyzing the FSAm-NPS dietary index (DI) as exposure. The pooled HRs associated with a 2-unit increase in the FSAm-NPS DI of all-cause mortality, CVD, and cancer risk were 1.06 (95% confidence interval [CI]: 0.99, 1.13; I2: 80%), 1.08 (95% CI: 1.00, 1.18; I2: 70%), and 1.09 (95% CI: 1.00, 1.19; I2: 77%), respectively. The Chilean Warning Label score and the Health Star Rating systems were examined by 1 study each and were significantly associated with the outcomes.
Conclusions
DIs underpinning most common FOP nutrition labels and reflecting nutrient-poor diets show a tendency toward an increased incidence of CVD and cancer, but the observed effects are quite modest in magnitude. Further studies at the population level are needed to support the widely shared hypothesis that FOP labels, possibly in conjunction with other interventions, may contribute to reduce noncommunicable disease risk.