Autoren:	Kolar, David R. Bühren, Katharina Herpertz-Dahlmann, Beate Becker, Katja Egberts, Karin Ehrlich, Stefan Fleischhaker, Christian Gontard, Alexander von Hahn, Freia Huss, Michael Jaite, Charlotte Kaess, Michael Legenbauer, Tanja Renner, Tobias J. Roessner, Veit Schulze, Ulrike Sinzig, Judith Wessing, Ida Hebebrand, Johannes Föcker, Manuel Jenetzky, Ekkehart
Titel:	Seasonal variation of BMI at admission in German adolescents with anorexia nervosa
Online-Publikationsdatum:	12-Sep-2018
Erscheinungsdatum:	2018
Sprache des Dokuments:	Englisch
Zusammenfassung/Abstract:	Objective Recent preliminary studies indicated a seasonal association of BMI at admission to inpatient treatment for anorexia nervosa (AN), indicating lower BMI in the cold season for restrictive AN. An impaired thermoregulation was proposed as the causal factor, based on findings in animal models of AN. However, findings regarding seasonality of BMI and physical activity levels in the general population indicate lower BMI and higher physical activity in summer than in winter. Therefore, we aimed to thoroughly replicate the findings regarding seasonality of BMI at admission in patients with AN in this study. Method AN subtype, age- and gender-standardized BMI scores (BMI-SDS) at admission, mean daily sunshine duration and ambient temperature at the residency of 304 adolescent inpatients with AN of the multi-center German AN registry were analyzed. Results A main effect of DSM-5 AN subtype was found (F(2,298) = 6.630, p = .002), indicating differences in BMI-SDS at admission between restrictive, binge/purge and subclinical AN. No main effect of season on BMI-SDS at admission was found (F(1,298) = 4.723, p = .025), but an interaction effect of DSM-5 subtype and season was obtained (F(2,298) = 6.625, p = .001). Post-hoc group analyses revealed a lower BMI-SDS in the warm season for restrictive AN with a non-significant small effect size (t(203.16) = 2.140, p = .033; Hedges′g = 0.28). Small correlations of mean ambient temperature (r = −.16) and daily sunshine duration (r = −.22) with BMI-SDS in restrictive AN were found. However, the data were widely scattered. Conclusions Our findings are contrary to previous studies and question the thermoregulatory hypothesis, indicating that seasonality in AN is more complex and might be subject to other biological or psychological factors, for example physical activity or body dissatisfaction. Our results indicate only a small clinical relevance of seasonal associations of BMI-SDS merely at admission. Longitudinal studies investigating within-subject seasonal changes might be more promising to assess seasonality in AN and of higher clinical relevance.
DDC-Sachgruppe:	150 Psychologie 150 Psychology
Veröffentlichende Institution:	Johannes Gutenberg-Universität Mainz
Organisationseinheit:	FB 04 Medizin
Veröffentlichungsort:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-808
URN:	urn:nbn:de:hebis:77-publ-584630
Version:	Published version
Publikationstyp:	Zeitschriftenaufsatz
Nutzungsrechte:	CC BY
Informationen zu den Nutzungsrechten:	https://creativecommons.org/licenses/by/4.0/
Zeitschrift:	PLOS ONE 13 9
Seitenzahl oder Artikelnummer:	e0203844
Verlag:	PLOS
Verlagsort:	San Francisco, California, US
Erscheinungsdatum:	2018
ISSN:	1932-6203
URL der Originalveröffentlichung:	http://dx.doi.org/10.1371/journal.pone.0203844
DOI der Originalveröffentlichung:	10.1371/journal.pone.0203844
Enthalten in den Sammlungen:	JGU-Publikationen