{"id":3053,"date":"2016-05-13T11:02:31","date_gmt":"2016-05-13T10:02:31","guid":{"rendered":"https:\/\/ounews.co\/?p=3053"},"modified":"2016-05-13T11:02:31","modified_gmt":"2016-05-13T10:02:31","slug":"ou-experts-pregnancy-fizzy-drinks-overweight-children-stats","status":"publish","type":"post","link":"https:\/\/www.open.ac.uk\/blogs\/news\/science-mct\/maths-statistics\/ou-experts-pregnancy-fizzy-drinks-overweight-children-stats\/","title":{"rendered":"OU expert on ‘pregnancy, artificial sweetener and overweight children’ stats"},"content":{"rendered":"

Research into women who consume diet fizzy drinks during pregnancy<\/a> has revealed they’re more likely to have overweight children by the time they reach their first birthday.\u00a0The study was conducted by a university in Canada with 3,000 women. But\u00a0Professor Kevin McConway<\/a>, Emeritus Professor of Applied Statistics at the OU, says casual conclusions can’t be drawn from this study and more research is needed…<\/em><\/p>\n

Should pregnant women stop drinking diet fizzy drinks now?<\/h2>\n

Given the data that they had to work with, this study is statistically competent. But it\u2019s important to be clear that their main conclusion is that ‘further research is warranted’, and certainly not that prospective mothers must stop drinking artificially sweetened drinks now. That\u2019s because of the limitations that are acknowledged clearly in the study report. What the mothers ate and drank was self-reported, so maybe there are inaccuracies. But crucially, this is an observational study, so causal conclusions can\u2019t be drawn.<\/p>\n

I\u2019ll spell that out. A fairly small group of these Canadian mothers \u2013 about\u00a0five per cent\u00a0of them \u2013 reported drinking artificially sweetened beverages at least once a day. (That includes diet soft drinks, and also tea or coffee with artificial sweetener added.)<\/p>\n

In other words, drinking these drinks once a day or more was a fairly unusual thing for Canadian mothers to do. You might expect that these unusual mothers would be different from the average in some ways, and indeed information in the study report shows that they were. For example, they were more likely to be overweight, to have smoked during pregnancy or to have had diabetes. On average they stopped breastfeeding earlier.<\/p>\n

\u201cThe study found that this group of mothers were also more likely to have babies who were overweight at one year old. Most of them \u2013 nearly 9 out of 10 \u2013 did not have overweight babies, but the chance of overweight was about double the chance for mothers who drank very few artificially sweetened drinks or none at all.<\/p>\n

They can’t know for sure<\/h2>\n

Perhaps that increased risk of overweight was indeed caused by the artificially sweetened drinks, or perhaps it was caused by something else that was unusual about the five per cent\u00a0of mothers. (In the jargon, perhaps the increased risk is due to confounders.)<\/p>\n

The researchers made statistical corrections to allow for differences in things they knew about, that may have made this group unusual apart from their sweetened drink consumption, such as maternal smoking and diabetes, a measure of the overall quality of their diet, the duration of breastfeeding, and several more. But they can\u2019t know for sure that they accounted for all these things completely, and there may be other aspects of these women\u2019s unusualness that could not be taken into account at all because they weren\u2019t recorded.<\/p>\n

So a study of this nature simply can\u2019t establish what causes the increased risk of overweight one-year-olds. The research report makes all this explicitly clear, and that\u2019s really why the conclusion can\u2019t go further than asking for more research.<\/p>\n","protected":false},"excerpt":{"rendered":"

Research into women who consume diet fizzy drinks during pregnancy has revealed they’re more likely to have overweight children by the time they reach their first birthday.\u00a0The study was conducted by a university in Canada with 3,000 women. But\u00a0Professor Kevin McConway, Emeritus Professor of Applied Statistics at the OU, says casual conclusions can’t be drawn […]<\/p>\n","protected":false},"author":2,"featured_media":3054,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[29],"tags":[1264,1762,1904,2113],"class_list":["post-3053","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-maths-statistics","tag-kevin-mcconway","tag-pregnancy","tag-research","tag-statistics"],"_links":{"self":[{"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/posts\/3053","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/comments?post=3053"}],"version-history":[{"count":0,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/posts\/3053\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/media\/3054"}],"wp:attachment":[{"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/media?parent=3053"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/categories?post=3053"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.open.ac.uk\/blogs\/news\/wp-json\/wp\/v2\/tags?post=3053"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}