National Health and Nutrition Examination Survey
Organization
Longitudinal study run by the CDC that has shown a decline in testosterone levels over time.
Mentioned in 2 videos
Videos Mentioning National Health and Nutrition Examination Survey

Improving Male Sexual Health, Function & Fertility | Dr. Michael Eisenberg
Andrew Huberman
Longitudinal study run by the CDC that has shown a decline in testosterone levels over time.

David Zeevi on Personalized Nutrition Based on Your Gut Microbiome
Y Combinator
A survey used to track changes in dietary intake, showing increased carbohydrate and decreased fat consumption in the US.