Consumption of ultra-processed foods and all-cause and cause-specific mortality in the Southern Community Cohort Study

Abstract

Background & aims: Higher intake of ultra-processed foods (UPF) has been linked with higher risks of cancer, cardiovascular disease, and diabetes, as well as all-cause mortality. However, studies on UPF and cause-specific mortality remain limited, especially among disadvantaged populations. We aimed to examine associations of UPF intake with all-cause and cause-specific mortality among low-income Americans.

Methods: In the Southern Community Cohort Study (SCCS), a prospective cohort of mostly low-income Black and White Americans, we included 77,060 participants who completed a food frequency questionnaire (FFQ) at baseline (2002-2009) and had at least 1 year follow-up. All 89 items in the FFQ were categorized using the Nova classification. UPF intake was calculated as % of daily foods intake by weight (grams). Cox regression was used to estimate HR (95% CI) for the association of UPF intake (quartile or per 10% increase) with total and cause-specific mortality (cancer, coronary heart disease [CHD], stroke, and diabetes) after adjusting for sociodemographics, lifestyles, and disease history.

Results: Of 77,060 participants, 46,175 (59.9%) were women, 49,857 were Black (64.7%), and mean age was 52.4 (SD: 8.8) years at baseline. The mean intake of UPF was 41.0% (SD: 15.7%). UPF intake was inversely associated with Healthy Eating Index and intakes of fiber, minerals, and vitamins but positively associated with intakes of sugars and fats (all P_FDR<0.0001). During an average follow-up of 12.2 years, we documented 17,895 total deaths, including 4267 from cancer, 2208 from CHD, 867 from stroke, and 997 from diabetes. In the fully adjusted model, higher UPF intake was not associated with all-cause, cancer, CHD, or stroke mortality but showed a significant association with increased diabetes mortality (HR [95% CI] = 1.32 [1.07, 1.62] for the highest versus lowest quartiles [>51.1% vs. <29.3%] and 1.09 [1.04, 1.15] per 10% increase). The adverse UPF-diabetes mortality association was noted regardless of sex, race, income, neighborhood deprivation, lifestyles, and cardiometabolic disease history, while particularly evident in participants with no more than high school education or a history of hypercholesterolemia (HR [95% CI] per 10% increase = 1.12 [1.05, 1.18] and 1.14 [1.07, 1.22], respectively; both P_interaction<0.05).

Conclusions: Among predominantly low-income Black and White American adults, UPF intake was associated with increased diabetes mortality, especially for individuals with limited education or hypercholesterolemia. Our findings suggest the potential impact of increasing access and intake of un/minimally processed food to replace UPF on reducing diabetes-related mortality among populations facing socioeconomic and health disparities.

Keywords: Diabetes mortality; Diet quality; Multi-ethnic populations; Prospective cohort study; Ultra-processed foods.