Sib­ling study shows eldest usu­ally the bright­est

The Weekend Australian - Travel - - Health - Com­piled by Dr Chris­tine White

THE eldest child is usu­ally smarter than their brothers and sis­ters, claims new re­search pub­lished this week in Science . The study shows that chil­dren raised as the eldest have higher intelligence quo­tients (IQ) than younger sib­lings. Even if older sib­lings have died, and a child is reared as the eldest, their IQ is higher by an av­er­age of 2.3 points com­pared to younger sib­lings. The find­ings are based on 243,939 Nor­we­gian men given an IQ test at the age of 18 or 19 as part of com­pul­sory mil­i­tary ser­vice. The scores, gath­ered be­tween 1985 and 2004, were on a stan­dard nine-point scale. Us­ing birth records, re­searchers ex­am­ined birth or­der and fam­ily sit­u­a­tion. They found the link be­tween IQ and birth or­der re­lated to so­cial birth or­der, rather than ac­tual birth or­der. Science 2007;316:1717 (Kris­tensen P, et al) BA­BIES with even one smok­ing par­ent have more than five times the lev­els of co­ti­nine — a toxic nico­tine by-prod­uct — in their urine than chil­dren of non-smok­ers. Pub­lished on­line this week in the ArchivesofDisea­sein Child­hood , the study in­volved 104 in­fants, 71 with at least one smok­ing par­ent and 33 with non-smok­ing par­ents. Co­ti­nine lev­els were mea­sured at 12 weeks of age. Com­pared to ba­bies of non-smok­ers, ba­bies with a smok­ing mother had four times the amount of co­ti­nine in their urine and those with a smok­ing fa­ther had dou­ble the amount. Sleep­ing with par­ents and a lower overnight tem­per­a­ture in the bed­room were also as­so­ci­ated with in­creased amounts of co­ti­nine in ba­bies’ urine. ArchDisChild 2007;doi:10.1136/adc.2006.108506 (Joseph DV, et al) CAL­CIUM from food is bet­ter for bones than sup­ple­ments, ac­cord­ing to new re­search ap­pear­ing in the Amer­i­canJour­nalofClin­i­cal Nu­tri­tion . Daily in­take from sup­ple­ments and diet, as well as bone min­eral den­sity (a mea­sure of bone strength), were stud­ied in 168 healthy post­menopausal women. Those who ob­tained at least 70 per cent of their cal­cium from dairy and other foods had sig­nif­i­cantly higher bone min­eral den­sity than those who got it from tablets. Sur­pris­ingly, this was true even though women get­ting their cal­cium from sup­ple­ments had a higher daily cal­cium in­take than those get­ting it from food. Only around 35 per cent of cal­cium in sup­ple­ments is ac­tu­ally ab­sorbed by the body, say the au­thors, which could ex­plain why the women with cal­cium-rich di­ets had health­ier bones. AmJClinNutri­tion 2007;85:1428-1433 (Napoli N, et al) ES­TRO­GEN ther­apy has been found to re­duce one of the risk fac­tors for heart dis­ease — good news for younger post-menopausal women want­ing es­tro­gen short-term to re­lieve hot flushes. Re­port­ing in theNew Eng­landJour­nalofMedicine this week, the au­thors also stress that hor­mone re­place­ment ther­apy is known to in­crease the risk of blood clots and stroke, so shouldn’t be used to pre­vent heart dis­ease. The study, part of the Women’s Health Ini­tia­tive, com­pared es­tro­gen (0.625 mil­ligrams per day) to in­ac­tive placebo pills in women 50 to 59 who had un­der­gone a hys­terec­tomy. Af­ter an av­er­age of 7.4 years of treat­ment, com­puter to­mog­ra­phy (CT) scan­ning on the hearts of 1064 of th­ese women showed those who took es­tro­gen had sig­nif­i­cantly lower lev­els of cal­cium build-up in their coro­nary ar­ter­ies than did women who took the placebo pills. NEnglJMed 2007;356:2591-2602 (Man­son JE, et al) PROSTATE can­cer risk could be low­ered by eat­ing a diet rich in omega-3 fatty acids, found in fish, wal­nuts and lin­seeds, sug­gests a study in the Jour­nalofClin­i­calIn­ves­ti­ga­tion this week. For up to 24 weeks, mice that are ge­net­i­cally sus­cep­ti­ble to prostate can­cer were fed one of three di­ets: high-omega-3, lowom­ega-3 or high-omega-6 (an­other fatty acid found in veg­etable oils). In each diet, 30 per cent of the en­ergy was from fat, 50 per cent from car­bo­hy­drates and 30 per cent from pro­teins. The omega-6/omega-3 ra­tio was 1:1 in the high-omega-3 diet, 20:1 in the lowom­ega-3 diet and 40:1 in the high-omega-6 diet. Com­pared to the other di­ets, the high­omega-3 diet slowed the growth of tu­mours and in­creased sur­vival time, whereas the high­omega-6 diet had the op­po­site ef­fect. The au­thors now plan to test the ben­e­fits of tak­ing omega-3 sup­ple­ments af­ter a prostate tu­mour has al­ready de­vel­oped. JClinIn­vest 2007;doi:10.1172/JCI31494 (Berquin IM, et al) DI­A­BETES can be dan­ger­ous even be­fore it’s full-blown, more than dou­bling the risk of dy­ing from heart dis­ease. The Aus­tralian study, led by El­iz­a­beth Barr at the In­ter­na­tional Di­a­betes In­sti­tute in Melbourne, shows ‘‘ pre-di­a­betes’’ — when the body be­gins strug­gling to process sugar — in­creases the risk of dy­ing from heart dis­ease by 2.5-fold com­pared to peo­ple with nor­mal blood sugar me­tab­o­lism. Pub­lished in the jour­nal Cir­cu­la­tion this week, the study in­volved 10,428 peo­ple tested for their abil­ity to process an oral dose of glu­cose. There were 298 deaths over the fol­low­ing five years, 88 due to heart dis­ease. Sixty-five per cent of those who died of heart dis­ease were ei­ther known di­a­bet­ics, newly-di­ag­nosed di­a­bet­ics, or had higher than nor­mal blood sugar lev­els. Ac­cord­ing to the au­thors, th­ese find­ings con­firm the im­por­tance of de­tect­ing and treat­ing pre-di­a­betes. Cir­cu­la­tion 2007;doi:10.1161/cir­cu­la­tion­aha. 106.685628 (Barr ELM, et al)

Food: Bet­ter than a tablet

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