TOHP randomized trials and mortality follow-up

The original TOHP consisted of two phases. TOHP I was carried out between September 1987 and January 1990, and evaluated the effects of four supplement and three lifestyle interventions, including weight loss and sodium reduction, on BP in 2182 men and women aged 30–54 years with high normal BP.31 TOHP II was carried out between December 1990 and March 1995, and evaluated the effects of sodium reduction and weight loss on BP using a 2 × 2 factorial design in 2382 men and women aged 30–54 years with pre-hypertension and a body mass index of 110–165% of desirable body weight.30 During the randomized trial periods, five to seven 24-h urine collections were scheduled over 18 months in TOHP I and three to five 24-h urine collections during 3–4 years in TOHP II. Because of possibly short-term intervention-related changes in sodium consumption, individuals in the active sodium-reduction group (327 in TOHP I and 1191 in TOHP II) were excluded from the current analysis. Another eight participants in TOHP I and seven in TOHP II were excluded due to missing sodium excretion. A further 3 participants in TOHP I and 17 in TOHP II were excluded due to the occurrence of an incident CVD event or death during the period of exposure assessment (i.e. the trial period). Thus, 1844 participants in TOHP I and 1167 participants in TOHP II were included in the current analysis.

The trial periods constitute the baseline period for subsequent follow-up. Post-trial follow-up was conducted for mortality beginning at the end of each trial period. A search of the National Death Index was carried out, accruing death information through December 2013.