Lessons Learned From Methodological Validation Research in E-Epidemiology

Abstract

Background: Traditional epidemiological research methods exhibit limitations leading to high logistics, human, and financial burden. The continued development of innovative digital tools has the potential to overcome many of the existing methodological issues. Nonetheless, Web-based studies remain relatively uncommon, partly due to persistent concerns about validity and generalizability.

Objective: The objective of this viewpoint is to summarize findings from methodological studies carried out in the NutriNet-Santé study, a French Web-based cohort study.

Methods: On the basis of the previous findings from the NutriNet-Santé e-cohort (>150,000 participants are currently included), we synthesized e-epidemiological knowledge on sample representativeness, advantageous recruitment strategies, and data quality.

Results: Overall, the reported findings support the usefulness of Web-based studies in overcoming common methodological deficiencies in epidemiological research, in particular with regard to data quality (eg, the concordance for body mass index [BMI] classification was 93%), reduced social desirability bias, and access to a wide range of participant profiles, including the hard-to-reach subgroups such as young (12.30% [15,118/122,912], <25 years) and old people (6.60% [8112/122,912], ≥65 years), unemployed or homemaker (12.60% [15,487/122,912]), and low educated (38.50% [47,312/122,912]) people. However, some selection bias remained (78.00% (95,871/122,912) of the participants were women, and 61.50% (75,590/122,912) had postsecondary education), which is an inherent aspect of cohort study inclusion; other specific types of bias may also have occurred.

Conclusions: Given the rapidly growing access to the Internet across social strata, the recruitment of participants with diverse socioeconomic profiles and health risk exposures was highly feasible. Continued efforts concerning the identification of specific biases in e-cohorts and the collection of comprehensive and valid data are still needed. This summary of methodological findings from the NutriNet-Santé cohort may help researchers in the development of the next generation of high-quality Web-based epidemiological studies.

Keywords: bias, epidemiology; cohort studies.

Figure 1

Design of the dietary data validation study, NutriNet-Santé, 2013 (N=199).

Figure 2

Comparison of the sociodemographic characteristics of NutriNet-Santé (2009-2014) subjects (N=122,912) with French census data. Gray bars denote NutriNet-Santé subjects. Black bars denote French Census estimates (2009) for individuals aged 18 years and above in metropolitan France from INSEE. All differences between NutriNet-Santé subjects and the Census estimates were statistically significant (all chi-square–test P values were <.001).²France: including Corsica and overseas territories.³Single: never-married, widowed, divorced, or separated.⁴Geographical distribution based on the Zone d'études et d'aménagement du territoire (ZEAT) defined by INSEE. INSEE: Institut national de la statistique et des études économiques.

Figure 3

Mean food (g/d) and beverage (ml/d) intake in the NutriNet-Santé study (2009-2010, N=49,443) and the nationally representative survey (ENNS, 2006-2007, n=2754). All data from both NutriNet-Santé and ENNS are weighted for age, education, presence of children in household, and season of data collection, using French 2007 Census data. ENNS: Etude Nationale Nutrition Santé.