formula.mod2 = hazstd ~ f(agc, model = "rw2") +
  f(district, model="besag", graph = g, param = c(1,0.01)) +
  f(distr.unstruct, model="iid", param = c(1,0.01)) +
  edu1 + edu2 + tpr + sex + bmi

mod2  =  inla(formula.mod2, data = Zambia, control.family = list(initial = 1),
  control.inla = list(h = 1e-4),
  control.compute = list(dic = TRUE,cpo=TRUE),
  verbose = TRUE)

names(mod2$summary.random$agc)
summary(mod2$summary.random$agc$"0.5quant")

library("ggplot2")

mydata <- as.data.frame(mod2$summary.random$agc)

ggplot(mydata) +
  geom_line(aes(ID, `0.5quant`)) +
  geom_line(aes(ID, `0.025quant`), linetype="dashed") +
  geom_line(aes(ID, `0.975quant`), linetype="dashed")