Among peo­ple in their 70s, anaemia may flag an in­creased risk of de­vel­op­ing de­men­tia lat­er in life, ac­cord­ing to a new study.

Re­searchers fol­low­ing more than 2,500 US adults in their 70s for over a decade found that those who start­ed out with anaemia were 65 per cent more like­ly to de­vel­op de­men­tia by the end of the study pe­ri­od.

"Anaemia is com­mon in the el­der­ly and oc­curs in up to 23 per cent of adults ages 65 and old­er," said se­nior au­thor Dr Kristi­na Yaffe of the Uni­ver­si­ty of Cal­i­for­nia, San Fran­cis­co.

Peo­ple with anaemia lack enough healthy red blood cells to car­ry oxy­gen through­out the body.

Few­er healthy red blood cells could mean less oxy­gen trav­el­ling to the brain and may re­sult in cog­ni­tive de­cline, she said.

Sev­er­al con­di­tions, in­clud­ing kid­ney dis­ease and nu­tri­tion­al de­fi­cien­cies, can cause anaemia.

Pre­vi­ous stud­ies have found an as­so­ci­a­tion be­tween anaemia and de­men­tia, but they had not fol­lowed anaemic adults over time to see if they de­vel­oped cog­ni­tive prob­lems, as the cur­rent study did, Yaffe told Reuters Health.

She and her coau­thors used med­ical records to fol­low 2,552 peo­ple be­tween the ages of 70 and 79 at the be­gin­ning of the study pe­ri­od. They were test­ed for anaemia ear­ly in the study and giv­en mem­o­ry and think­ing tests over a to­tal of 11 years.

At the start of the study, 393 par­tic­i­pants had anaemia. And at the end of the study, 445, or about 18 per cent of par­tic­i­pants, had de­vel­oped de­men­tia, based on records of their hos­pi­tal vis­its, pre­scribed de­men­tia med­ica­tion use or a sig­nif­i­cant down­ward change on the mem­o­ry and think­ing tests.

Of the rough­ly 400 men and women who were anaemic at the start, 23 per cent de­vel­oped de­men­tia, com­pared to 17 per cent of the 2,000 oth­ers who were not anaemic, ac­cord­ing to the re­sults pub­lished in the jour­nal Neu­rol­o­gy.

That six per cent dif­fer­ence is a large change in risk on a pop­u­la­tion lev­el, Yaffe said.

"I think doc­tors should be aware of this im­por­tant con­nec­tion es­pe­cial­ly as both anaemia and de­men­tia are com­mon with ag­ing," she said.

The in­creased risk for de­men­tia linked to anaemia did not change based on race or gen­der.

De­spite the as­so­ci­a­tion, the study does not prove that anaemia caus­es de­men­tia, cau­tioned Dr Ruth Pe­ters, who re­search­es risk fac­tors for de­men­tia at Im­pe­r­i­al Col­lege Lon­don and was not in­volved in the new study.

"There are many risk fac­tors that are as­so­ci­at­ed with de­men­tia and these kinds of stud­ies are very use­ful in iden­ti­fy­ing and clar­i­fy­ing these," she told Reuters Health by e-mail. "Each in­di­vid­ual will have their own mo­sa­ic of risk fac­tors."

It is pos­si­ble that a third in­flu­ence, like chron­ic kid­ney dis­ease, caused both anaemia and de­men­tia in the par­tic­i­pants with both con­di­tions, but the au­thors tried to rule that out, Yaffe said.

Low iron lev­els, which are one cause of anaemia, can cause heart prob­lems for old­er peo­ple, so doc­tors usu­al­ly check iron and rec­om­mend get­ting more of it from foods like spinach or over the counter vi­t­a­mins if lev­els are low, she said.

"How­ev­er, a third of the time, doc­tors can­not find a com­mon cause for the low­er haemo­glo­bin lev­els (anaemia) in old­er adults," said Dr Raj Shah of Rush Uni­ver­si­ty Med­ical Cen­ter in Chica­go.

Anaemia can al­so re­sult from poor nu­tri­tion, bleed­ing dis­or­ders or can­cer, among oth­er things, said Shah, who stud­ies cog­ni­tive de­cline in old­er peo­ple but was not in­volved in the study.

"We still have to un­der­stand what is the mech­a­nism by which low haemo­glo­bin is as­so­ci­at­ed with cog­ni­tive de­cline and risk of de­vel­op­ing de­men­tia in old­er per­sons," Shah told Reuters Health. Fu­ture re­search should in­ves­ti­gate whether cor­rect­ing anaemia al­so im­proves cog­ni­tive health, Yaffe said. (Reuters)

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