structure(list(study = c("DART", "DART", "London Corn/Olive", 
"London Corn/Olive", "London Corn/Olive", "London Low Fat", "London Low Fat", 
"Minnesota Coronary", "Minnesota Coronary", "MRC Soya", "MRC Soya", 
"Oslo Diet-Heart", "Oslo Diet-Heart", "STARS", "STARS", "Sydney Diet-Heart", 
"Sydney Diet-Heart", "Veterans Administration", "Veterans Administration", 
"Veterans Diet & Skin CA", "Veterans Diet & Skin CA"), treatment = c("control", 
"diet", "control", "diet", "diet", "control", "diet", "control", 
"diet", "control", "diet", "control", "diet", "control", "diet", 
"control", "diet", "control", "diet", "control", "diet"), responders = c(113L, 
111L, 1L, 5L, 3L, 24L, 20L, 248L, 269L, 31L, 28L, 65L, 48L, 3L, 
1L, 28L, 39L, 177L, 174L, 2L, 1L), exposure = c(1917, 1925, 43.6, 
41.3, 38, 393.5, 373.9, 4715, 4823, 715, 751, 885, 895, 87.8, 
91, 1011, 939, 1544, 1588, 125, 123)), row.names = c(NA, -21L
), class = "data.frame")