Study: Drinking up to 5–8 glasses of wine or beer a week not seen to increase dementia risk

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There may be a link between alco­hol and demen­tia, but it’s com­pli­cat­ed (Pop­u­lar Science):

“A recent arti­cle in the British Med­ical Jour­nal has rekin­dled the sci­en­tif­ic argu­ment over the rela­tion­ship between abstain­ing from alco­hol and devel­op­ing demen­tia. The study involved 9,000 civ­il ser­vants work­ing in Lon­don, all of whom were aged between 35 and 55 when the study began between 1985 and 1988. When the study end­ed in 1993, their aver­age age was 50. The par­tic­i­pants’ med­ical records were ana­lyzed to iden­ti­fy diag­noses of dementia—more than 23 years, on aver­age, after the study had fin­ished. The results found that absti­nence in midlife was asso­ci­at­ed with a 45% high­er risk of devel­op­ing demen­tia, com­pared with peo­ple who con­sumed between one and 14 units of alco­hol per week … The find­ings for those who drank above the rec­om­mend­ed 14 units a week were per­haps less sur­pris­ing. For every sev­en unit per week increase above 14 units there was a sig­nif­i­cant 17% increase in the risk of demen­tia … We should also be aware that between one-quar­ter and two-thirds of old­er peo­ple start drink­ing more than the rec­om­mend­ed 14 unit lim­it for the first time after the age of 60.”

Note: 14 units of alco­hol means 5–8 glass­es of wine/ beer, depend­ing on size and strength. The full descrip­tion is: 14 sin­gle mea­sures of spir­its (ABV 37.5%); sev­en pints of aver­age-strength (4%) lager; nine and one-third 125ml glass­es of aver­age-strength (12%) wine; sev­en 175ml glass­es of aver­age-strength (12%) wine; four and two-thirds 250ml glass­es of aver­age-strength (12%) wine.

The Study:

Alco­hol con­sump­tion and risk of demen­tia: 23 year fol­low-up of White­hall II cohort study (British Med­ical Journal):

  • Objec­tive: To exam­ine the asso­ci­a­tion between alco­hol con­sump­tion and risk of dementia.
  • Design: Prospec­tive cohort study.
  • Main out­come mea­sures: Inci­dent demen­tia, iden­ti­fied through link­age to hos­pi­tal, men­tal health ser­vices, and mor­tal­i­ty reg­is­ters until 2017. Mea­sures of alco­hol con­sump­tion were the mean from three assess­ments between 1985/88 and 1991/93 (midlife), cat­e­gorised as absti­nence, 1–14 units/week, and >14 units/week…
  • Con­clu­sion: The risk of demen­tia was increased in peo­ple who abstained from alco­hol in midlife or con­sumed >14 units/week. In sev­er­al coun­tries, guide­lines define thresh­olds for harm­ful alco­hol con­sump­tion much high­er than 14 units/week. The present find­ings encour­age the down­ward revi­sion of such guide­lines to pro­mote cog­ni­tive health at old­er ages … Tak­en togeth­er, these results sug­gest that absten­tion and exces­sive alco­hol con­sump­tion are asso­ci­at­ed with an increased risk of demen­tia, although the under­ly­ing mech­a­nisms are like­ly to be dif­fer­ent in the two groups. Over­all, no evi­dence was found that alco­hol con­sump­tion between 1 unit/week and 14 units/week increas­es the risk of dementia.

The Study in Context: