Heart at­tack risk higher with cal­cium, says study

The Weekend Australian - Travel - - Health - Adam Cress­well Health ed­i­tor

TAK­ING cal­cium sup­ple­ments — a com­mon treat­ment to strengthen bones — may put healthy older women at higher risk of heart at­tacks. New Zealand re­searchers fol­lowed nearly 1500 women for up to five years — half of whom took cal­cium, while the rest took dummy pills — and found there were

up­ward trends’’ in rates of heart at­tack, stroke and other heart prob­lems among women tak­ing the cal­cium.

The re­sults ap­pear to con­tra­dict the ex­pec­ta­tions raised by some pre­vi­ous stud­ies, which sug­gested cal­cium may have a pro­tec­tive ef­fect on the heart. How­ever, the ex­tent of any in­crease in heart risk is hard to de­ter­mine from the new study.

The women di­rectly in­volved in the re­search, all of whom were healthy and aged over 55, ap­peared to have dou­ble the rel­a­tive risk of heart at­tack if they took cal­cium.

But the au­thors said that this risk was halved — to the point where it might no longer be sta­tis­ti­cally sig­nif­i­cant — af­ter they used hospi­tal ad­mis­sion data to fac­tor in other heart in­ci­dents that were not picked up dur­ing the trial it­self.

The au­thors of the study, pub­lished on­line this week by the Bri­tish Med­i­cal Jour­nal, con­ceded the re­sults were not con­clu­sive’’.

But they did sug­gest that high cal­cium in­takes might have an ad­verse ef­fect’’ on heart health, par­tic­u­larly in el­derly peo­ple with poor kid­ney func­tion.

The present data do not per­mit de­fin­i­tive con­clu­sions to be reached in this re­gard but do flag car­diac health as an area of con­cern in re­la­tion to cal­cium use,’’ wrote the au­thors, from the Univer­sity of Auck­land.

Aus­tralian ex­perts praised the re­searchers’ meth­ods but said the find­ings should not scare peo­ple away from cal­cium if their di­etary in­take was de­fi­cient.

John Eis­man, di­rec­tor of the Bone and Min­eral Re­search Pro­gram at Syd­ney’s Gar­van In­sti­tute of Med­i­cal Re­search, said the re­sults showed that over the five years of the study, there was a dif­fer­ence of just 10 women who had heart at­tack, stroke or sud­den death be­tween the 732 women in the cal­cium group and the 739 women who took dummy pills.

That means if you had 1000 women treated (with cal­cium) for a year, it’s po­ten­tially pos­si­ble that three women would have one of th­ese events,’’ Pro­fes­sor Eis­man said.

It’s hard to know if this (ef­fect of cal­cium) is real or not.

I think all you can say is, there might be a small risk — and that peo­ple shouldn’t think that cal­cium is some sort of panacea that cures ev­ery­thing.’’

Peo­ple whose di­ets con­tained lit­tle cal­cium would be ad­vised to con­tinue tak­ing sup­ple­ments, while those with ad­e­quate di­ets might want to re­con­sider, he said.

An­other ex­pert, Pro­fes­sor Jack Martin, from the Bone, Joint and Can­cer Unit at St Vin­cent’s In­sti­tute in Melbourne, said the study was small and the re­sults would need to be repli­cated in larger tri­als be­fore any change in cur­rent prac­tice were to be con­sid­ered’’.

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