Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort.
BMJ (Clinical research ed.). 2018;360:k322
Plain language summary
Foods that are heavily processed tend to have high levels of total fat, sugar and salt and low levels of fibre and vitamins. They also tend to have high levels of contaminants (caused for example by high heat treatment), food additives and plastic packaging exposure. This large prospective population-based cohort study assessed the association between ultra-processed food consumption and the incidence of cancer. The study found that ultra-processed food intake was associated with a higher overall cancer risk and a higher breast cancer risk. A 10% increase in the consumption of ultra-processed foods was associated with an increase of more than 10% greater risk of overall and breast cancer risk. The authors call for further studies to better understand the different elements of food processing and their association to cancer risk.
OBJECTIVE To assess the prospective associations between consumption of ultra-processed food and risk of cancer. DESIGN Population based cohort study. SETTING AND PARTICIPANTS 104 980 participants aged at least 18 years (median age 42.8 years) from the French NutriNet-Santé cohort (2009-17). Dietary intakes were collected using repeated 24 hour dietary records, designed to register participants' usual consumption for 3300 different food items. These were categorised according to their degree of processing by the NOVA classification. MAIN OUTCOME MEASURES Associations between ultra-processed food intake and risk of overall, breast, prostate, and colorectal cancer assessed by multivariable Cox proportional hazard models adjusted for known risk factors. RESULTS Ultra-processed food intake was associated with higher overall cancer risk (n=2228 cases; hazard ratio for a 10% increment in the proportion of ultra-processed food in the diet 1.12 (95% confidence interval 1.06 to 1.18); P for trend<0.001) and breast cancer risk (n=739 cases; hazard ratio 1.11 (1.02 to 1.22); P for trend=0.02). These results remained statistically significant after adjustment for several markers of the nutritional quality of the diet (lipid, sodium, and carbohydrate intakes and/or a Western pattern derived by principal component analysis). CONCLUSIONS In this large prospective study, a 10% increase in the proportion of ultra-processed foods in the diet was associated with a significant increase of greater than 10% in risks of overall and breast cancer. Further studies are needed to better understand the relative effect of the various dimensions of processing (nutritional composition, food additives, contact materials, and neoformed contaminants) in these associations. STUDY REGISTRATION Clinicaltrials.gov NCT03335644.
Breast cancer risk markedly lower with serum 25-hydroxyvitamin D concentrations ≥60 vs <20 ng/ml (150 vs 50 nmol/L): Pooled analysis of two randomized trials and a prospective cohort.
PloS one. 2018;13(6):e0199265
Plain language summary
Numerous studies have shown an association between Vitamin D status and risk of breast cancer. However to date, there are few studies that look at concentrations of Vitamin D in excess of 100 nmol/l and breast cancer risk. This study pooled the results of 2 randomised controlled trials and one prospective cohort study to investigate the relationship between Vitamin D levels and breast cancer incidence. The pooled results included 5,038 women. The analysis revealed that women with Vitamin D status of >150 nmol/l had an 80% lower risk of breast cancer than women with Vitamin D concentrations of <50 nmol/l, adjusting for age, BMI, smoking status and calcium supplementation. The findings also show that the risk of breast cancer is dose responsive, with the lowest risk of breast cancer at Vitamin D levels of >150 nmol/l. Testing for Vitamin D status and optimising levels to >150 nmol/l could be considered as part of a strategy for breast cancer prevention.
BACKGROUND While numerous epidemiologic studies have found an association between higher serum 25-hydroxyvitamin D [25(OH)D] concentrations and lower breast cancer risk, few have assessed this association for concentrations >40 ng/ml. OBJECTIVE To investigate the relationship between 25(OH)D concentration and breast cancer risk across a broad range of 25(OH)D concentrations among women aged 55 years and older. METHODS Analyses used pooled data from two randomized clinical trials (N = 1129, N = 2196) and a prospective cohort (N = 1713) to examine a broad range of 25(OH)D concentrations. The outcome was diagnosis of breast cancer during the observation periods (median: 4.0 years). Three analyses were conducted: 1) Incidence rates were compared according to 25(OH)D concentration from <20 to ≥60 ng/ml (<50 to ≥150 nmol/L), 2) Kaplan-Meier plots were developed and 3) multivariate Cox regression was used to examine the association between 25(OH)D and breast cancer risk using multiple 25(OH)D measurements. RESULTS Within the pooled cohort (N = 5038), 77 women were diagnosed with breast cancer (age-adjusted incidence: 512 cases per 100,000 person-years). Results were similar for the three analyses. First, comparing incidence rates, there was an 82% lower incidence rate of breast cancer for women with 25(OH)D concentrations ≥60 vs <20 ng/ml (Rate Ratio = 0.18, P = 0.006). Second, Kaplan-Meier curves for concentrations of <20, 20-39, 40-59 and ≥60 ng/ml were significantly different (P = 0.02), with the highest proportion breast cancer-free in the ≥60 ng/ml group (99.3%) and the lowest proportion breast cancer-free in the <20 ng/ml group (96.8%). The proportion with breast cancer was 78% lower for ≥60 vs <20 ng/ml (P = 0.02). Third, multivariate Cox regression revealed that women with 25(OH)D concentrations ≥60 ng/ml had an 80% lower risk of breast cancer than women with concentrations <20 ng/ml (HR = 0.20, P = 0.03), adjusting for age, BMI, smoking status, calcium supplement intake, and study of origin. CONCLUSIONS Higher 25(OH)D concentrations were associated with a dose-response decrease in breast cancer risk with concentrations ≥60 ng/ml being most protective.