Growth hormone concentration and risk of all-cause and cardiovascular mortality: The REasons for Geographic And Racial Disparities in Stroke (REGARDS) study.

BACKGROUND AND AIMS: Identifying individuals at elevated risk for mortality, especially from cardiovascular disease, may help guide testing and treatment. Risk factors for mortality differ by sex and race. We investigated the association of growth hormone (GH) with all-cause and cardiovascular mortality in a racially diverse cohort in the United States. METHODS: Among an age, sex and race stratified subgroup of 1046 Black and White participants from the REasons for Geographic And Racial Disparities in Stroke (REGARDS) study, 881 had GH available; values were log2 transformed. Associations with all-cause and cardiovascular mortality were assessed in the whole subgroup, and by sex and race, using multivariable Cox-proportional hazard models and C-index. RESULTS: The mean age was 67.4 years, 51.1% were women, and 50.2% were Black participants. The median GH was 280 (interquartile range 79-838) ng/L. There were 237 deaths and 74 cardiovascular deaths over a mean of 8.0 years. In multivariable Cox analysis, GH was associated with higher risk of all-cause mortality per doubling (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.09-1.25) and cardiovascular mortality (HR 1.21, 95% CI 1.06-1.37). The association did not differ by sex or race (interaction p > 0.05). The addition of GH to a model of clinical variables significantly improved the C-index compared to clinical model alone for all-cause and cardiovascular death. CONCLUSIONS: Higher fasting GH was associated with higher risk of all-cause and cardiovascular mortality and improved risk prediction, regardless of sex or race.