298 e-Letters

  • Abnormal liver enzymes and diabetes risk: potential contribution of chronic viral hepatitis was underplayed
    Gee Yen Shin

    Xu et al report an association between deranged liver enzymes e.g. alanine transaminase (ALT) in Chinese people residing in Southern China and the incidence of diabetes [1].

    The authors examined multiple potential confounding factors which could influence liver enzymes e.g. alcohol consumption & adiposity. However, although the authors briefly mentioned chronic viral hepatitis infections i.e. chronic hepatitis B...

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  • Potential Challenges to Using Paternal Education as a Proxy for SES
    Dakota J Inglis

    Oksuzyan et al. report an association between race/ethnicity and two subtypes of childhood leukemia: acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML).1 Accordingly, the researchers suggest that there are genetic, cultural, and environmental factors involved in the etiology of childhood leukaemia [1].

    Importantly, Oksuzyan et al. made a significant effort to examine and control for the poten...

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  • Evidence of a lack of beneficial effect of outdoor physical exercise
    Tze Wai Wong

    Dear sir

    The author commented on the paucity of research on the point where physical exercise in polluted air becomes more harmful than beneficial. I would like to share our research findings conducted more than 10 years ago in Hong Kong (Yu et al, 2004). We compared the physical fitness of school children who regularly performed physical exercise with those who did not. In a less polluted district (annual mean P...

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  • Self-reported passive smoking and salivary cotinine concentration
    Tomoyuki Kawada

    Batty et al. conducted a follow-up study to know the effect of passive smoking on subsequent mortality [1]. In men in their study, self- reported passive smoking, not salivary cotinine, could predict mortality. From their Tables 1 and 2, salivary cotinine level was categorized into three groups, and self-reported passive smoking was categorized binary. I have a query on the association between self-reported passive smokin...

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  • Re:Extreme temperatures and paediatric emergency
    Zhiwei Xu

    Dear Sir, Thank you very much for your interest in our research. In our JECH paper, we analyzed data on a broad range of pediatric diseases and found, generally, children aged 10-14 years are more vulnerable to both hot and cold effects, compared with children of other age groups. In the OEM paper, we analyzed pediatric asthma data and found, specifically, children aged 10-14 years are more sensitive to the adverse impact...

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  • Trajectories for each cohort need to span the same/ similar age range
    William Johnson

    The three cohorts in this study were as follows:

    Cohort 1: born 1970s and followed between ~15-35 years of age

    Cohort 2: born 1950s and followed between ~35-55 years of age

    Cohort 3: born 1930s and followed between ~55-75 years of age

    This study design has serious limitations for the investigation of cohort differences in BMI trajectories (and therefore also for the investigation of...

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  • Is 7 a day really better than 5 a day?
    Robert J Hancox

    These impressive data have been widely reported. Eating plenty of fruit and vegetables seems to be a good idea, but I am concerned at how the need to eat 7+ portions a day to obtain maximum benefit has been reported. As far as I can tell, the estimates for "daily" consumption were based on a single day. Few people eat exactly the same every day and regression to the mean suggests that most of those who ate 7+ portions on...

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  • Re:What exactly is a vegetable?
    Oyinlola Oyebode

    Dear Prof. Bland,

    Please see our supplementary material where you can see the questions that were asked during the interview. You will note that survey participants were explicitly advised not to include potatoes when considering their answers.

    http://jech.bmj.com/content/suppl/2014/03/04/jech-2013- 203500.DC1/jech-2013-203500supp1.pdf

    Conflict of Interest:


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  • Air pollution and respiratory symptoms in children
    Tomoyuki Kawada

    Molter et al. reported the effects of long-term exposure to particulate matter with aerodynamic diameter <10 micrometer (PM10) and nitrogen dioxide (NO2) on the prevalence of asthma and wheeze within a population-based birth cohort (1). They concluded that no significant association between long-term exposure to PM10 and NO2 and the prevalence of either asthma or wheeze was found. In contrast, the same authors report...

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  • What exactly is a vegetable?
    John M Bland

    I may have missed it, but Oyebode et al. do not seem to say exactly what they mean by a vegetable or what the exact question was. This is important, because they do refer to a UK Department of Health website, which states that potatoes, yams, plantain, and casava should not be included the 5-a-day count, but sweetcorn should. I thought that sweetcorn was a grain and so would not count it as a vegetable, though I may b...

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