I read the bits about an 80-year old longitudinal study, and my spidey-sense said, "Ternan." That appears to be valid, as this would appear to be the Mr. Friedman of the University of California (Riverside) mentioned in the article: http://www.faculty.ucr.edu/~friedman/longabstract.html
Kern, M. L. & Friedman, H. S. (2008). Early educational milestones as predictors of lifelong academic achievement, midlife adjustment, and longevity. Journal of Applied Developmental Psychology.
This study gathered follow-up data from the Terman Life Cycle Study (N = 1,023) to examine how age at first reading and age at school entry relate to grade school academic performance, lifelong educational attainment, midlife health and mental adjustment, and longevity across eight decades. Early reading was associated with early academic success, but less lifelong educational attainment and worse midlife adjustment. Early school entry was associated with less educational attainment, worse midlife adjustment, and most importantly, increased mortality risk. Personality, midlife adjustment, and educational attainment partially mediated the school entry-longevity association (controlling for age, sex, personal characteristics, and home environment factors). Although the sample is limited in some respects and care should be taken in generalizing the results, findings do confirm the importance of lifespan approaches in understanding the effects of education on individual patterns within social contexts.
That final phrase "within social contexts" seems important. If you think things have changed a bit since the 1930s, this data set is not for you.
