Relationship of serum zinc levels to hand preference, skull length and serum gonadal hormone levels in right-handed young adults.

Abstract

The association between serum zinc (Zn) level and the degree of hand preference was studied in right-handed young adults. Hand preference was scored by the Waterloo Handedness Questionnaire. Serum Zn level was determined by the flow injection analysis-atomic absorption technique. Zinc was found to be positively linearly and significantly correlated with the degree of right hand preference in the sample of males with familial sinistrality (FS+) and FS- females with right eye and right foot preference. There was a negative linear correlation between these variables in FS+ females. Skull length showed a significant negative linear correlation with zinc in FS+ males and females, but a positive linear correlation in FS- females. In FS- females, there was a significant positive linear correlation between serum gonadal hormone binding globulin (GBG) and serum Zn levels. In FS+ males, there was a significant negative linear correlation between serum GBG and Zn levels, and a significant positive linear correlation between serum free testosterone level and serum Zn level. It was suggested that zinc may influence the degree of the right hand preference by hormonal mechanisms according to genetically established brain organization.