A study of HCV infection among injecting drug users. All injecting drug users were interviewed by means of a standardized face-to-face interview and information on their socio-demographic status, drug use history, drug use, and related risk behavior was recorded
Format
A data frame with 3 variables:
- dur
Duration of injection/Exposure time (years)
- seropositive
If the individual is seropositive or not
Source
Mathei, C., Shkedy, Z., Denis, B., Kabali, C., Aerts, M., Molenberghs, G., Van Damme, P. and Buntinx, F. (2006), Evidence for a substantial role of sharing of injecting paraphernalia other than syringes/needles to the spread of hepatitis C among injecting drug users. Journal of Viral Hepatitis, 13: 560-570. doi:10.1111/j.1365-2893.2006.00725.x
Examples
# Reproduce Fig 4.3, p. 66
library(dplyr)
# snapping age to aggregated age group
# (credit: https://stackoverflow.com/a/12861810)
groups <- c(0.5:24.5)
range <- 0.5
low <- findInterval(hcv_be_2006$dur, groups)
high <- low + 1
low_diff <- hcv_be_2006$dur - groups[ifelse(low == 0, NA, low)]
high_diff <- groups[ifelse(high == 0, NA, high)] - hcv_be_2006$dur
mins <- pmin(low_diff, high_diff, na.rm = TRUE)
pick <- ifelse(!is.na(low_diff) & mins == low_diff, low, high)
hcv_be_2006$dur <- ifelse(
mins <= range + .Machine$double.eps, groups[pick], hcv_be_2006$dur
)
hcv_be_2006 <- hcv_be_2006 %>%
group_by(dur) %>%
summarise(tot = n(), pos = sum(seropositive))
plot(
hcv_be_2006$dur, hcv_be_2006$pos / hcv_be_2006$tot,
cex = 0.1 * hcv_be_2006$tot, pch = 16,
xlab = "duration of injection (years)",
ylab = "seroprevalence", xlim = c(0, 25), ylim = c(0, 1)
)
