ABSTRACT
Résumé Les études épidémiologiques d’observation à grande échelle fournissent des informations essentielles au développement des politiques de prévention des maladies chroniques comme l’obésité. Depuis 2009, 29 études sur l’obésité ont été publiées à partir des données de la cohorte française NutriNet-Santé. L’objectif de cet article est d’en présenter pour la première fois une synthèse et d’en déduire l’apport de NutriNet-Santé à la compréhension de l’obésité. Parmi ces études, 5 ont investigué les conséquences de l’obésité, 23 ses déterminants, et 1 son rôle médiateur. Parmi les conséquences de l’obésité étudiées, des facteurs comme la migraine ou la dyspepsie fonctionnelle ont été positivement associés à l’obésité. En revanche, parmi les déterminants de l’obésité, de nombreux facteurs liés à l’alimentation ont été positivement associés à l’obésité (ex : proportion d’aliments ultra-transformés au sein des apports) ou inversement associés (ex : alimentation issue de l’agriculture biologique). Aussi, certains facteurs psychologiques ont été positivement associés (ex : impulsivité) ou inversement associés (ex : optimisme) à l’obésité. Dans NutriNet-Santé, de nouvelles études en lien avec l’obésité sont en cours sur des sujets peu traités comme le COVID-19 ou les troubles mentaux. Summary Large-scale observational epidemiological studies provide essential information for the development of prevention policies for chronic diseases such as obesity. Since 2009, the French NutriNet-Santé cohort has been used as the basis for 29 empirical studies on obesity. The aim of this review is to present a summary of the findings of those studies and to deduce the contribution of NutriNet-Santé to the understanding of obesity. Among the 29 studies, 5 analyzed obesity as an exposure variable, 23 – as an outcome, and 1 – as a moderator. When modelled as a determinant (or exposure), obesity was cross-sectionally and positively associated with migraine and functional dyspepsia, respectively. In turn, when modelled as a consequence (or outcome), obesity was positively associated with different dietary factors, such as the proportion of ultra-processed foods in the diet and preference for fatty food. Other factors were inversely associated with obesity, such as following an organic diet. Some psychological factors were positively (e.g. impulsivity) or inversely associated (e.g. optimism) with obesity risk. In NutriNet-Santé, further studies on obesity are underway, dealing with its association with COVID-19 and mental disorders.
ABSTRACT
BACKGROUND: Nutritional factors are essential for the functioning of the immune system and could therefore play a role in COVID-19 but evidence is needed. Our objective was to study the associations between diet and the risk of SARS-CoV-2 infection in a large population-based sample. METHODS: Our analyses were conducted in the French prospective NutriNet-Santé cohort study (2009-2020). Seroprevalence of anti-SARS-CoV-2 antibodies was assessed by ELISA on dried blood spots. Dietary intakes were derived from repeated 24 h dietary records (at least 6) in the two years preceding the start of the COVID-19 pandemic in France (February 2020). Multi-adjusted logistic regression models were computed. RESULTS: A total of 7766 adults (70.3% women, mean age: 60.3 years) were included, among which 311 were positive for anti-SARS-CoV-2 antibodies. Dietary intakes of vitamin C (OR for 1 SD=0.86 (0.75-0.98), P=0.02), vitamin B9 (OR=0.84 (0.72-0.98), P=0.02), vitamin K (OR=0.86 (0.74-0.99), P=0.04), fibers (OR=0.84 (0.72-0.98), P=0.02), and fruit and vegetables (OR=0.85 (0.74-0.97), P=0.02) were associated to a decreased probability of SARS-CoV-2 infection while dietary intakes of calcium (OR=1.16 (1.01-1.35), P=0.04) and dairy products (OR=1.19 (1.06-1.33), P=0.002) associated to increased odds. No association was detected with other food groups or nutrients or with the overall diet quality. CONCLUSIONS: Higher dietary intakes of fruit and vegetables and, consistently, of vitamin C, folate, vitamin K and fibers were associated with a lower susceptibility to SARS-CoV-2 infection. Beyond its established role in the prevention of non-communicable diseases, diet could therefore also contribute to prevent some infectious diseases such as COVID-19.
Subject(s)
COVID-19 , Adult , Cohort Studies , Female , Humans , Male , Middle Aged , Pandemics , Prospective Studies , Risk Factors , SARS-CoV-2 , Seroepidemiologic StudiesABSTRACT
BACKGROUND: Since December 2019, coronavirus disease 2019 (COVID-19) has been spreading steadily, resulting in overwhelmed health-care systems and numerous deaths worldwide. To counter these outcomes, many countries, including France, put in place strict lockdown measures, requiring the temporary closure of all but essential places and causing an unprecedented disruption of daily life. OBJECTIVES: Our objective was to explore potential changes in dietary intake, physical activity, body weight, and food supply during the COVID-19 lockdown and how these differed according to individual characteristics. METHODS: The analyses included 37,252 adults from the French web-based NutriNet-Santé cohort who completed lockdown-specific questionnaires in April-May 2020. Nutrition-related changes and their sociodemographic, lifestyle, and health-status correlates were investigated using multivariable logistic regression models. Clusters of participants were defined using an ascending hierarchical classification of change profiles derived from multiple correspondence analyses. RESULTS: During the lockdown, trends of unfavorable changes were observed: decreased physical activity (reported by 53% of the participants), increased sedentary time (reported by 63%), increased snacking, decreased consumption of fresh food (especially fruit and fish), and increased consumption of sweets, cookies, and cakes. Yet, the opposite trends were also observed: increased home cooking (reported by 40%) and increased physical activity (reported by 19%). Additionally, 35% of the participants gained weight (mean weight gain in these individuals, 1.8 kg ± SD 1.3 kg) and 23% lost weight (2 kg ± SD 1.4 kg weight loss). All of these trends displayed associations with various individual characteristics. CONCLUSIONS: These results suggest that nutrition-related changes occurred during the lockdown in both unfavorable and favorable directions. The observed unfavorable changes should be considered in the event of a future lockdown, and should also be monitored to prevent an increase in the nutrition-related burden of disease, should these diet/physical activity changes be maintained in the long run. Understanding the favorable changes may help extend them on a broader scale. This trial was registered at clinicaltrials.gov as NCT03335644.