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Where in the world? Latitude, longitude and season contribute to the complex co-ordinates determining cortisol levels.
Clin Endocrinol (Oxf). 2018 09; 89(3):299-307.CE

Abstract

OBJECTIVE

Cortisol is a critical stress hormone with circadian rhythms synchronized by light. There are seasonal differences in expression of pro-inflammatory genes and in some diseases moderated by glucocorticoids. As light changes with season and with latitude and longitude, we assessed changes in population cortisol associated with these parameters.

DESIGN

Retrospective data audit.

PATIENTS

Populations across 4 states of Australia over 3 years.

MEASUREMENTS

Serum cortisol levels, age, gender, time of collection, sunrise time, season and location were determined.

RESULTS

In 4 geographically separate populations (n = 84 937), sunrise time and time of sample collection were the most important factors influencing median cortisol. Over 2 hours in the morning cortisol could decrease by up to 76 nmol/L, and for each hour that sunrise time advanced there was up to 6.9% increase in cortisol. A cyclic seasonal pattern of cortisol was confirmed each year in all populations with autumn/winter cortisol highest compared to spring/summer with differences of up to 44 nmol/L. There was less change in cortisol in latitudes closer to the equator but cortisol progressively increased from 25 to 30°S of the equator. In more southerly latitudes, seasonal cortisol variation also increased, and over the entire latitude range, there was up to 50 nmol/L change in cortisol. Longitude variation within a time zone had a minimal effect on median cortisol.

CONCLUSIONS

Location, time of year and time of day are important influences on population cortisol levels. Elevated autumn/winter morning cortisol levels are likely due to sampling closer to the circadian peak due to later sunrise time. Understanding how the environment can influence cortisol levels may further our knowledge of physiology and disease.

Links

Publisher Full Text (DOI)

Authors+Show Affiliations

Hadlow N
Department of Clinical Biochemistry, PathWest Laboratory Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia. School of Pathology and Laboratory Medicine, University of Western Australia, Crawley, Western Australia, Australia.
Brown S
Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.
Wardrop R
Department of Clinical Biochemistry, PathWest Laboratory Medicine, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.
Conradie J
Department of Biochemistry, Western Diagnostic Pathology, Myaree, Western Australia, Australia.
Henley D
Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia. School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia.

MeSH

AdultAgedCircadian RhythmFemaleGeographyHumansHydrocortisoneMaleMiddle AgedModels, TheoreticalRetrospective StudiesSeasons

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29846966

Citation

Hadlow, Narelle, et al. "Where in the World? Latitude, Longitude and Season Contribute to the Complex Co-ordinates Determining Cortisol Levels." Clinical Endocrinology, vol. 89, no. 3, 2018, pp. 299-307.
Hadlow N, Brown S, Wardrop R, et al. Where in the world? Latitude, longitude and season contribute to the complex co-ordinates determining cortisol levels. Clin Endocrinol (Oxf). 2018;89(3):299-307.
Hadlow, N., Brown, S., Wardrop, R., Conradie, J., & Henley, D. (2018). Where in the world? Latitude, longitude and season contribute to the complex co-ordinates determining cortisol levels. Clinical Endocrinology, 89(3), 299-307. https://doi.org/10.1111/cen.13754
Hadlow N, et al. Where in the World? Latitude, Longitude and Season Contribute to the Complex Co-ordinates Determining Cortisol Levels. Clin Endocrinol (Oxf). 2018;89(3):299-307. PubMed PMID: 29846966.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Where in the world? Latitude, longitude and season contribute to the complex co-ordinates determining cortisol levels. AU - Hadlow,Narelle, AU - Brown,Suzanne, AU - Wardrop,Robert, AU - Conradie,Johan, AU - Henley,David, Y1 - 2018/06/21/ PY - 2018/03/14/received PY - 2018/05/27/revised PY - 2018/05/28/accepted PY - 2018/5/31/pubmed PY - 2019/11/9/medline PY - 2018/5/31/entrez KW - Cortisol KW - circadian KW - circannual KW - latitude KW - light KW - longitude KW - season KW - summer KW - winter SP - 299 EP - 307 JF - Clinical endocrinology JO - Clin Endocrinol (Oxf) VL - 89 IS - 3 N2 - OBJECTIVE: Cortisol is a critical stress hormone with circadian rhythms synchronized by light. There are seasonal differences in expression of pro-inflammatory genes and in some diseases moderated by glucocorticoids. As light changes with season and with latitude and longitude, we assessed changes in population cortisol associated with these parameters. DESIGN: Retrospective data audit. PATIENTS: Populations across 4 states of Australia over 3 years. MEASUREMENTS: Serum cortisol levels, age, gender, time of collection, sunrise time, season and location were determined. RESULTS: In 4 geographically separate populations (n = 84 937), sunrise time and time of sample collection were the most important factors influencing median cortisol. Over 2 hours in the morning cortisol could decrease by up to 76 nmol/L, and for each hour that sunrise time advanced there was up to 6.9% increase in cortisol. A cyclic seasonal pattern of cortisol was confirmed each year in all populations with autumn/winter cortisol highest compared to spring/summer with differences of up to 44 nmol/L. There was less change in cortisol in latitudes closer to the equator but cortisol progressively increased from 25 to 30°S of the equator. In more southerly latitudes, seasonal cortisol variation also increased, and over the entire latitude range, there was up to 50 nmol/L change in cortisol. Longitude variation within a time zone had a minimal effect on median cortisol. CONCLUSIONS: Location, time of year and time of day are important influences on population cortisol levels. Elevated autumn/winter morning cortisol levels are likely due to sampling closer to the circadian peak due to later sunrise time. Understanding how the environment can influence cortisol levels may further our knowledge of physiology and disease. SN - 1365-2265 UR - https://www.unboundmedicine.com/medline/citation/29846966/Where_in_the_world_Latitude_longitude_and_season_contribute_to_the_complex_co_ordinates_determining_cortisol_levels_ DB - PRIME DP - Unbound Medicine ER -