# Include Foreign Package To Read SAS Transport Files
library(foreign)

# Create Temporary File To Store Downloaded SAS Transport Files
tf <- tempfile()

# Download NHANES 1999-2000 Demographic Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/1999-2000/DEMO.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
DEMO <- read.xport(tf)[,c("SEQN","SDDSRVYR","RIDSTATR","RIDPREG","SDMVPSU","SDMVSTRA","WTMEC4YR","RIAGENDR","RIDAGEYR","RIDRETH1")]

# Download NHANES 2001-2002 Demographic Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/2001-2002/DEMO_B.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest
DEMO_B <- read.xport(tf)[,c("SEQN","SDDSRVYR","RIDSTATR","RIDPREG","SDMVPSU","SDMVSTRA","WTMEC4YR","RIAGENDR","RIDAGEYR","RIDRETH1")]

# Append Demographic Data
DEMO_4Yr <- rbind(DEMO, DEMO_B)

# Download NHANES 1999-2000 Blood Pressure Exam Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/1999-2000/BPX.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
BPX <- read.xport(tf)[,c("SEQN","BPXSY1","BPXSY2","BPXSY3","BPXSY4","BPXDI1","BPXDI2","BPXDI3","BPXDI4")]

# Download NHANES 2001-2002 Blood Pressure Exam Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/2001-2002/BPX_B.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
BPX_B <- read.xport(tf)[,c("SEQN","BPXSY1","BPXSY2","BPXSY3","BPXSY4","BPXDI1","BPXDI2","BPXDI3","BPXDI4")]

# Append Blood Pressure Exam Data
BPX_4Yr <- rbind(BPX, BPX_B)

# Download NHANES 1999-2000 Blood Pressure Questionnaire Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/1999-2000/BPQ.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
BPQ <- read.xport(tf)[,c("SEQN","BPQ010","BPQ020","BPQ030","BPQ050A","BPQ070","BPQ080","BPQ100D")]

# Download NHANES 1999-2000 Blood Pressure Questionnaire Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/2001-2002/BPQ_B.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
BPQ_B <- read.xport(tf)[,c("SEQN","BPQ010","BPQ020","BPQ030","BPQ050A","BPQ070","BPQ080","BPQ100D")]

# Append Blood Pressure Questionnaire Data
BPQ_4Yr <- rbind(BPQ, BPQ_B)

# Download NHANES 1999-2000 Medical Conditions Questionnaire Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/1999-2000/MCQ.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
MCQ <- read.xport(tf)[,c("SEQN","MCQ160B","MCQ160C","MCQ160D","MCQ160E","MCQ160F")]

# Download NHANES 2001-2002 Medical Conditions Questionnaire Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/2001-2002/MCQ_B.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
MCQ_B <- read.xport(tf)[,c("SEQN","MCQ160B","MCQ160C","MCQ160D","MCQ160E","MCQ160F")]

# Append Medical Conditions Questionnaire Data
MCQ_4Yr <- rbind(MCQ, MCQ_B)

# Download NHANES 1999-2000 Cholesterol Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/1999-2000/LAB13.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
LAB13 <- read.xport(tf)[,c("SEQN","LBXTC")]

# Download NHANES 2001-2002 Cholesterol Data To Temporary File
download.file("ftp://ftp.cdc.gov/pub/Health_Statistics/NCHS/nhanes/2001-2002/L13_B.xpt", tf, mode="wb")
# Create Data Frame From Temporary File & Keep Variables Of Interest                                              
L13_B <- read.xport(tf)[,c("SEQN","LBXTC")]

# Append Cholesterol Data 
LAB13_4Yr <- rbind(LAB13, L13_B)