APOE and dementia: This complements previous studies that found an association between snoring and higher cognitive function among older adults over a shorter follow-up period of 10 years.9 In contrast, no such association was found in a relatively younger sample (mean 52.3 years) with a longer follow-up of 22.5 years.23 A previous cross-sectional study of non-demented older adults also found that APOE ε4 carriers reported less snoring than non-carriers.24 The direction of the phenotypic association between snoring and dementia was further supported by our univariate MR results.