Footnotes

• Contributors CW, JF and AZ were involved in the conception and design of the study. EFT, MJB, SAJ, JF and AZ were involved in data collection, analysis and interpretation. EFT and AZ drafted the work. All authors have critically revised this letter and approved the final version to be published.

• Funding This project was funded by a grant from the Top Institute Food and Nutrition, Wageningen (GH001) to CW and a Netherlands Organization for Scientific Research grant (NWO-VIDI 864.13.013) to JF. AZ holds a Rosalind Franklin Fellowship (University of Groningen).

• Competing interests None declared.

• Ethics approval The LifeLines-DEEP study was approved by the ethics committee of the University Medical Centre Groningen, document no. METC UMCG LLDEEP: M12.113965. All participants signed an informed consent form prior to study enrolment.

• Provenance and peer review Not commissioned; internally peer reviewed.