library(survey)
library(RNHANES)
library(tidyverse)

dat <- nhanes_load_data("EPHPP_H", "2013-2014", demographics = TRUE) %>%
  filter(!is.na(URXBPH), !is.na(URXBP3))

des <- nhanes_survey_design(dat, "WTSB2YR")

logmean <- svymean(~log(URXBPH), des, na.rm = TRUE)

# Geometric mean lower 95% confidence interval
exp(logmean[1] - 1.96 * sqrt(attr(logmean, "var")))

# Geometric mean
exp(logmean)[1]

# Geometric mean upper 95% confidence interval
exp(logmean[1] + 1.96 * sqrt(attr(logmean, "var")))