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March 10, 2016

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Being short or overweight linked to reduced life chances

March 10, 2016
Courtesy of The BMJ
and World Science staff

Be­ing a short man or an over­weight woman is as­so­ci­at­ed with low­er chances in life in ar­eas such as educa­t­ion, oc­cupa­t­ion, and in­come, con­cludes a new study.

It’s well es­tab­lished that high­er so­ci­o­ec­on­om­ic sta­tus is as­so­ci­at­ed with bet­ter health and long­er life. In de­vel­oped coun­tries, be­ing taller and thin­ner are as­so­ci­at­ed with high­er so­ci­o­ec­on­o­mic sta­tus, the re­search­ers be­hind the new study said, but still un­clear are is­sues such as which are the causes and which are the ef­fects.

The re­search­ers, led by Tim­o­thy Frayling at the Un­ivers­ity of Ex­e­ter in the U.K., an­a­lyzed ge­net­ic vari­ants with known ef­fects on height and body mass in­dex, a meas­ure of weight sta­tus, from 119,000 peo­ple aged be­tween 40 and 70. The in­forma­t­ion came from the U.K. Biobank, a da­tabase of bi­o­log­i­cal in­forma­t­ion from half a mil­lion Brit­ish adults.

The re­search­ers used a sta­tis­ti­cal tech­nique called men­de­li­an ran­dom­iza­t­ion, a meth­od that pro­po­nents say avoids some of the prob­lems that af­flict ob­serva­t­ional stud­ies, mak­ing the re­sults less prone to bi­as and un­meas­ured con­found­ing fac­tors.

The in­ves­ti­ga­tors as­sessed five meas­ures of so­ci­o­ec­on­om­ic sta­tus: age com­plet­ing full time educa­t­ion, de­gree lev­el educa­t­ion, job class, an­nu­al house­hold in­come, and a so­cial de­priva­t­ion score known as the Town­send de­priva­t­ion in­dex.

They found that shorter height, as es­ti­mat­ed by ge­net­ics, leads to low­er lev­els of educa­t­ion, low­er job sta­tus, and less in­come, par­tic­u­larly in men, and that high­er body mass in­dex leads to low­er in­come and great­er de­priva­t­ion in wom­en.

Var­i­ous fac­tors could link taller stat­ure to high­er so­cial po­si­tion, but the study did­n’t con­sid­er which of these fac­tors were in­volved, said the in­ves­ti­ga­tors. But the re­search­ers—whose find­ings ap­peared March 8 in The BMJ, form­erly the Brit­ish Med­i­cal Journal—said pos­si­bil­i­ties in­clude com­plex in­ter­ac­tions be­tween self-es­teem, stig­ma, pos­i­tive dis­crimina­t­ion, and in­creased in­tel­li­gence.

“These da­ta sup­port ev­i­dence that height and BMI [body mass in­dex] play an im­por­tant par­tial role in de­ter­min­ing sev­er­al as­pects of a per­son’s so­ci­o­ec­on­om­ic sta­tus, es­pe­cially wom­en’s BMI for in­come and de­priva­t­ion and men’s height for educa­t­ion, in­come, and job class,” they wrote.

“These find­ings have im­por­tant so­cial and health im­plica­t­ions, sup­porting ev­i­dence that over­weight peo­ple, es­pe­cially wom­en, are at a dis­ad­vant­age and that taller peo­ple, es­pe­cially men, are at an ad­van­tage.”

Open da­ta pro­jects such as U.K. Bio­bank of­fer great op­por­tun­i­ties for ad­vanc­ing un­der­stand­ing in this field, say ex­perts at the Un­ivers­ity of Bris­tol in an ac­com­pa­nying ed­i­to­ri­al. How­ev­er, they point out that “im­por­tant caveats ex­ist even to this in­ter­preta­t­ion” and call for “an ap­pro­pri­ately care­ful ap­proach to da­ta anal­y­sis and in­ter­preta­t­ion.”


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Being a short man or an overweight woman is associated with lower chances in life in areas such as education, occupation, and income, concludes a study published on March 8. It’s well established that higher socioeconomic status is associated with better health and longer life. In developed countries, being taller and thinner are associated with higher socioeconomic status, the researchers behind the new study said, but still unclear are issues such as which are the causes and which are the effects. The researchers, led by Timothy Frayling at the University of Exeter in the U.K., analyzed genetic variants with known effects on height and body mass index, a measure of weight status, from 119,000 people aged between 40 and 70. The information came from the U.K. Biobank, a database of biological information from half a million British adults. The researchers used a statistical technique called mendelian randomisation, a method that proponents say avoids some of the problems that afflict observational studies, making the results less prone to bias and unmeasured confounding factors. The investigators assessed five measures of socioeconomic status: age completing full time education, degree level education, job class, annual household income, and a social deprivation score known as the Townsend deprivation index. The results show that shorter height, as estimated by genetics, leads to lower levels of education, lower job status, and less income, particularly in men, and that higher body mass index leads to lower income and greater deprivation in women. Various factors could link taller stature to higher social position, but the study didn’t consider which of these factors were involved, said the investigators. But the researchers—whose findings appear in The BMJ, formerly the British Medical Journal—said possibilities include complex interactions between self-esteem, stigma, positive discrimination, and increased intelligence. “These data support evidence that height and BMI [body mass index] play an important partial role in determining several aspects of a person’s socioeconomic status, especially women’s BMI for income and deprivation and men’s height for education, income, and job class,” they wrote. “These findings have important social and health implications, supporting evidence that overweight people, especially women, are at a disadvantage and that taller people, especially men, are at an advantage.” Open data projects such as U.K. Biobank offer great opportunities for advancing understanding in this field, say experts at the University of Bristol in an accompanying editorial. However, they point out that “important caveats exist even to this interpretation” and call for “an appropriately careful approach to data analysis and interpretation.”