Lower digit ratio (2D:4D) in alcohol dependence: Confirmation and exploratory analysis in a population‐based study of young men

Abstract

Moderately sized, case‐control studies have related alcohol dependence in middle‐aged in‐patients to lower second‐to‐fourth finger length ratio (2D:4D), a proxy for prenatal hyperandrogenization. As primary aim, we here intended to confirm that lower 2D:4D is also associated with Diagnostic and Statistical Manual of Mental Disorders (DSM)–IV/‐5 alcohol dependence and alcohol use disorder in a large population‐based cohort of young males. Exploratory aims included underlying mechanisms. We analyzed self‐reported data on 2D:4D, DSM‐IV/‐5 criteria, anticipated subjective responses to alcohol, and willingness to purchase alcoholic drinks from 4989 Swiss men of the Cohort Study on Substance Use Risk Factors (C‐SURF). The mean of right‐hand 2D:4D and left‐hand 2D:4D was lower in men with DSM‐IV alcohol dependence than in those without (0.975 vs 0.981, P = .035) and lower in men with moderate to severe (0.974) than in those with mild (0.982, P = .001) or no (0.981, P = .003) DSM‐5 alcohol use disorder. Moreover, mean 2D:4D was lower in those reporting recent use of health services due to substance use problems (0.968 vs 0.981, P = .046). Lower mean 2D:4D correlated with a stronger anticipation to feel high following alcohol consumption (total cohort: ρ = −0.033, P = .026) and with a willingness to purchase more higher‐priced alcoholic drinks (DSM‐IV alcohol dependence subgroup: ρmin = −0.162, P = .002). This is the first population‐based study on young males to demonstrate lower 2D:4D in DSM‐IV alcohol dependence, DSM‐5 alcohol use disorder, and the related use of health care services. We also provide novel insight into cognitive‐behavioral mechanisms. These results should help to establish more effective preventive and therapeutic strategies targeting 2D:4D and prenatal androgen exposure.

Lower Digit Ratio (2D:4D) Indicative of Excess Prenatal Androgen Is Associated With Increased Sociability and Greater Social Capital

“…Separate values for right-hand 2D:4D (R2D:4D), left-hand 2D:4D (L2D:4D), and the difference between R2D:4D and L2D:4D (2D:4Dr-l) were defined as exploratory predictors. Moreover, regarding quality control, we refer to a previous analysis of the same cohort (except for 9 patients with missing data on alcohol-related questions) which showed median values of 2D:4D similar to other studies (Lenz et al, 2019a).…”

“…Subsequent, we calculated the mean of right-hand 2D:4D and left-hand 2D:4D (M2D:4D) which served as our primary predictor. Whereas some studies report that target traits are more strongly related to 2D:4D of the right hand (Manning et al, 1998; Hönekopp and Watson, 2010; Kornhuber et al, 2011; Masuya et al, 2015; Bilgic et al, 2016), other report stronger associations with 2D:4D of the left hand (Muller et al, 2012; Kornhuber et al, 2013; Hong et al, 2014; Lenz et al, 2017, 2019a). As far as we know, there is no reliable explanation for different associations of right- and left-hand 2D:4D with prenatal androgen load.…”

“…Thus, associations between 2D:4D and health further highlight the importance to understand the role of prenatal androgen exposure in adult social behavior. For example, in males, lower 2D:4D has been associated with lower anxiety (Evardone and Alexander, 2009), a higher risk for conduct problems during childhood (Eichler et al, 2018), addictive and substance use disorders (Kornhuber et al, 2011, 2013; Canan et al, 2017, 2019; Lenz et al, 2017, 2018a, 2019a; Siegmann et al, 2019), suicide (Lenz et al, 2016, 2019b), and reduced life expectancy in adulthood (Lenz and Kornhuber, 2018).…”

Digit ratio (2D:4D) and transgender identity: new original data and a meta-analysis

“…This study investigated a possible association of 2D:4D and transsexuality in a large sample. It was part of the Finger Length in Psychiatry (FLIP) project 13 , 20 – 27 , a line of independent studies aiming to elucidate the role of prenatal sex hormone organization in the etiopathogenesis of psychiatric disorders in childhood, adolescence, and adulthood, such as addictive disorders 22 , 26 , 28 , 29 , 30 , suicide completion 31 , or behavioral symptoms in children 32 . Another goal was to establish prevention targets and strategies based on this model 33 .…”

Sex‐Dependent Alcohol Instrumentalization Goals in Non‐Addicted Alcohol Consumers versus Patients with Alcohol Use Disorder: Longitudinal Change and Outcome Prediction

“…A summary of general drug instrumentalization goals was suggested by Müller and Schumann (2011a, 2011b). For some of the instrumentalization goals, neurobiological mechanisms of action have now emerged (Lenz et al, 2009, 2020; Müller, 2020; Müller et al, 2017; Müller and Kornhuber, 2017).…”