Country-level gender inequality is associated with structural differences in the brains of women and men
Authors: Zugman André , Alliende Luz María , Medel Vicente , Bethlehem Richard A.I. , Seidlitz Jakob , Ringlein Grace , Arango Celso , Arnatkevičiūtė Aurina , Asmal Laila , Bellgrove Mark , Benegal Vivek , Bernardo Miquel , Billeke Pablo , Bosch-Bayard Jorge , Bressan Rodrigo , Busatto Geraldo F. , Castro Mariana N. , Chaim-Avancini Tiffany , Compte Albert , Costanzi Monise , Czepielewski Leticia , Dazzan Paola , de la Fuente-Sandoval Camilo , Di Forti Marta , Díaz-Caneja Covadonga M. , María Díaz-Zuluaga Ana , Du Plessis Stefan , Duran Fabio L. S. , Fittipaldi Sol , Fornito Alex , Freimer Nelson B. , Gadelha Ary , Gama Clarissa S. , Garani Ranjini , Garcia-Rizo Clemente , Gonzalez Campo Cecilia , Gonzalez-Valderrama Alfonso , Guinjoan Salvador , Holla Bharath , Ibañez Agustín , Ivanovic Daniza , Jackowski Andrea , Leon-Ortiz Pablo , Lochner Christine , López-Jaramillo Carlos , Luckhoff Hilmar , Massuda Raffael , McGuire Philip , Miyata Jun , Mizrahi Romina , Murray Robin , Ozerdem Aysegul , Pan Pedro M. , Parellada Mara , Phahladira Lebogan , Ramirez-Mahaluf Juan P. , Reckziegel Ramiro , Reis Marques Tiago , Reyes-Madrigal Francisco , Roos Annerine , Rosa Pedro , Salum Giovanni , Scheffler Freda , Schumann Gunter , Serpa Mauricio , Stein Dan J. , Tepper Angeles , Tiego Jeggan , Ueno Tsukasa , Undurraga Juan , Undurraga Eduardo A. , Valdes-Sosa Pedro , Valli Isabel , Villarreal Mirta , Winton-Brown Toby T. , Yalin Nefize , Zamorano Francisco , Zanetti Marcus V. ,   cVEDA, Winkler Anderson M. , Pine Daniel S. , Evans-Lacko Sara , Crossley Nicolas A. , Murthy Pratima , Chakrabarti Amit , Basu Debasish , Subodh B.N. , Singh Lenin , Singh Roshan , Kalyanram Kartik , Kartik Kamakshi , Kumaran Kalyanaraman , Krishnaveni Ghattu , Kuriyan Rebecca , Kurpad Sunita Simon , Barker Gareth J. , Bharath Rose D. , Desrivieres Sylvane , Purushottam Meera , Orfanos Dimitri P. , Sharma Eesha , Hickman Matthew , Heron Jon , Toledano Mireille B. , Vaidya Nilakshi 
Published: May 2023

Gender inequality across the world has been associated with a higher risk to mental health problems and lower academic achievement in women compared to men. We also know that the brain is shaped by nurturing and adverse socio-environmental experiences. Therefore, unequal exposure to harsher conditions for women compared to men in gender-unequal countries might be reflected in differences in their brain structure, and this could be the neural mechanism partly explaining women’s worse outcomes in gender-unequal countries. We examined this through a random-effects meta-analysis on cortical thickness and surface area differences between adult healthy men and women, including a meta-regression in which country-level gender inequality acted as an explanatory variable for the observed differences. A total of 139 samples from 29 different countries, totaling 7,876 MRI scans, were included. Thickness of the right hemisphere, and particularly the right caudal anterior cingulate, right medial orbitofrontal, and left lateral occipital cortex, presented no differences or even thicker regional cortices in women compared to men in gender-equal countries, reversing to thinner cortices in countries with greater gender inequality. These results point to the potentially hazardous effect of gender inequality on women’s brains and provide initial evidence for neuroscience-informed policies for gender equality.