Associations between dietary pesticide residue mixture exposure and mortality in a population-based prospective cohort of men and women.

Background: There is a concern that pesticide residues, regularly detected in foods, might pose a health risk to the consumer, but epidemiological evidence is limited. We assessed the associations between dietary exposure to a mixture of pesticide residues and mortality.

Methods: Food consumption was assessed in 68,844 participants from the Swedish Mammography Cohort and the Cohort of Swedish Men, 45-83 years at baseline (1997). Concentrations of pesticide residues detected in foods on the Swedish market (1996-1998), mainly fruits and vegetables, were obtained via monitoring programs. To assess mixture effects, we summed per food item the ratios of each single pesticide mean residue concentration divided by its acceptable daily intake to create for each participant a Dietary Pesticide Hazard Index (adjusted for energy intake and expressed per kilogram of body weight). Multivariable-adjusted Cox proportional hazards models were used to estimate hazard ratios (HR) and 95 % confidence intervals (95 %CI).

Results: During 15 years of follow-up (1998-2014), a total of 16,527 deaths occurred, of which 6,238 were caused by cardiovascular disease (CVD) and 5,364 by cancer. Comparing extreme quintiles of Dietary Pesticide Hazard Index, the highest category was inversely associated with CVD mortality HR, 0.82 (95 % CI, 0.75-0.90) and with cancer mortality HR 0.82 (95 % CI 0.75-0.91). In analyses stratified by high/low Dietary Pesticide Hazard Index, similar inverse associations were observed by increasing fruit and vegetable consumption.

Conclusions: We observed no indications that dietary exposure to pesticide residue mixtures was associated with increased mortality, nor any clear indications that the benefits of fruit and vegetable consumption on mortality was compromised. Yet, our results need to be interpreted with caution.