Altitude may contribute to regional variation in methamphetamine use in the United States: a population database study.
OBJECTIVE
Methamphetamine (MA) use rates in the United States (US) have consistently demonstrated geographical variation and have been higher in the West and Midwest. This uneven pattern of use could be explained by regional differences in MA manufacturing and distribution, but may also result from differences in altitude. The hypobaric hypoxia found at high altitude alters neurotransmitter synthesis in the brain, which may contribute to MA use. The present study investigated the relationship between mean altitude and MA use rate in the 48 contiguous US states and the District of Columbia.


METHODS
State-level estimates of past year MA use were extracted from the National Survey on Drug Use and Health report. The mean altitude of each state was calculated using the Shuttle Radar Topography Mission altitude data set.


RESULTS
There was a significant positive correlation between mean state altitude and MA use rate (r=0.66, p<0.0001). Multivariate linear regression analysis showed that altitude remained a significant predictor for MA use rate (β=0.36, p=0.02), after adjusting for age, ethnicity, education, socioeconomic level, employment, MA laboratory incidents, subpopulations, and other substance use.


CONCLUSIONS
Altitude appears to a possible contributing factor for regional variation of MA use in the US. Further studies will be required to determine biological changes in neurotransmission resulting from chronic mild hypoxia at high altitude in MA users.
The Brain Institute, University of Utah, Salt Lake City, UT, USA. ; Department of Psychiatry, University of Utah School of Medicine, Salt Lake City, UT, USA. ; Department of Psychiatry, The Catholic University of Korea College of Medicine, Seoul, Republic of Korea.
Tae-Suk
TS
Kim
The Brain Institute, University of Utah, Salt Lake City, UT, USA. ; Department of Psychiatry, University of Utah School of Medicine, Salt Lake City, UT, USA. ; VISN 19 MIRECC, Salt Lake City Veterans Affairs Health Care System, Salt Lake City, UT, USA.
Douglas G
DG
Kondo
Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Seoul, Republic of Korea.
Namkug
N
Kim
The Brain Institute, University of Utah, Salt Lake City, UT, USA. ; Department of Psychiatry, University of Utah School of Medicine, Salt Lake City, UT, USA. ; VISN 19 MIRECC, Salt Lake City Veterans Affairs Health Care System, Salt Lake City, UT, USA.
Perry F
PF
Renshaw
Altitude; Elevation; Hypoxia; Methamphetamine; Neurotransmission