Four meta-analyses across 164 studies on atypical footedness prevalence and its relation to handedness

Abstract

Human lateral preferences, such as handedness and footedness, have interested researchers for decades due to their pronounced asymmetries at the population level. While there are good estimates on the prevalence of handedness in the population, there is no large-scale estimation on the prevalence of footedness. furthermore, the relationship between footedness and handedness still remains elusive. Here, we conducted meta-analyses with four different classification systems for footedness on 145,135 individuals across 164 studies including new data from the ALSPAC cohort. the study aimed to determine a reliable point estimate of footedness, to study the association between footedness and handedness, and to investigate moderating factors influencing footedness. We showed that the prevalence of atypical footedness ranges between 12.10% using the most conservative criterion of left-footedness to 23.7% including all left-and mixed-footers as a single nonright category. As many as 60.1% of left-handers were left-footed whereas only 3.2% of right-handers were left-footed. Males were 4.1% more often non-right-footed compared to females. Individuals with psychiatric and neurodevelopmental disorders exhibited a higher prevalence of non-right-footedness. Furthermore, the presence of mixed-footedness was higher in children compared to adults and leftfootedness was increased in athletes compared to the general population. finally, we showed that footedness is only marginally influenced by cultural and social factors, which play a crucial role in the determination of handedness. overall, this study provides new and useful reference data for laterality research. furthermore, the data suggest that footedness is a valuable phenotype for the study of lateral motor biases, its underlying genetics and neurodevelopment.

Quantitative multidimensional phenotypes improve genetic analysis of laterality traits

“…Similar to the results obtained by Suzuki et al 34 , the item “foot used to kick a ball”, which is often used as the only assessment item in footedness studies, does not seem to be the optimal choice to investigate heritability of laterality. We previously showed that measuring footedness in terms of kicking results in a similar prevalence of left-footedness 29 compared to inventories such as the Waterloo footedness questionnaire (WFQ) 67 or lateral preference inventory (LPI) 68 . However, as kicking is often only assessed in one trial, the prevalence of mixed-footedness is systematically lower in studies using kicking to assess footedness 29 .…”

“…We previously showed that measuring footedness in terms of kicking results in a similar prevalence of left-footedness 29 compared to inventories such as the Waterloo footedness questionnaire (WFQ) 67 or lateral preference inventory (LPI) 68 . However, as kicking is often only assessed in one trial, the prevalence of mixed-footedness is systematically lower in studies using kicking to assess footedness 29 . Equally the low SNP-h 2 for eye preference in ALSPAC could reflect the poor quality of this phenotype.…”

“…Previous research has shown a tendency towards a higher probability of left-sided lateral preferences in left-handers. For example, 60% of left-handers and 3% of right-handers are left-footed 29 and 57% of left-handers and 35% of right-handers are left-eye dominant 69 . These patterns suggest that a common dimension of left/right asymmetry underlies hand, foot, and eye preference 70 .…”

“…Foot and eye preference have received considerably less attention than handedness, even though associations with neurodevelopmental disorders have been reported for these phenotypes as well. We previously found a higher prevalence of non-right-footedness in neurodevelopmental and psychiatric disorders including schizophrenia, dyslexia, and depression ( n cases = 2,431; n controls = 116,938) 29 . Smaller studies point to higher rates of left eye preference in schizophrenia ( n cases = 88; n controls = 118 30 ; n cases = 68; n controls = 944 31 ) and ASD ( n cases = 37; n controls = 20) 32 .…”

Human Lateralization, Maternal Effects and Neurodevelopmental Disorders

“…Nevertheless, it must be noted that motor functions deserve a special place in this list, particularly because of the peculiar status of handedness as a function that is lateralized both behaviorally and neurologically from early childhood (Bondi et al, 2020 ): around 90% of humans show a preference for using the right hand, which is controlled by the left brain hemisphere (McManus, 2002 ; Tommasi, 2009 ). Additionally, footedness should also be granted a special position in the field of human laterality, having been shown to share similarities with handedness both in behavioral and neuropsychological terms, and to be less influenced by cultural and social factors than handedness (Elias and Bryden, 1998 ; Tran et al, 2014 ; Packheiser et al, 2020a , c ). Population-level motor asymmetries which seem to be precursors of handedness are observed already during fetal life (Hepper et al, 1990 ; Hepper, 2013 ; see also Baciadonna et al, 2010 for analogous early predictors of limb laterality in a non-human species), speaking in favor of a substantial genetic contribution.…”