Preventive Medicine 52 (2011) 291–292

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Preventive Medicine

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This Month in Preventive Medicine

Obesity: Two interesting ideas

0091-7435/$ – see front mdoi:10.1016/j.ypmed.2011.

We are excited to publish the papers byWilliams (2011) and Pigeyre et al. (2011) in this month'sissue of PreventiveMedicine because they provide broader than usual reflections about the evolutionof the obesity epidemic.

Based on the U.S. National Walker's Health Study (National Walker's Health Study, 1997),Williams (2011) reports on the results of a mail survey conducted in 2000 of people who wereinterested enough in walking to subscribe to a walkingmagazine or to participate in walking events.The survey yield for the analyses comprised 33,015 non-smoking adults (26,587 women and 6428men) who provided self-reported data on usual walking distance and body mass index (BMI, kg/m2), as well as semi-qualitative data on their parents' adiposity (ordinal categories: lean; normal;overweight; very overweight). The lowest quartile of walking intensity in this population was“b1.5 km/day”, the upper limit of which is around one mile per day. In a general population survey,perhaps 80% of the respondents would report walking less than 1.5 km/day. Howmuch do youwalkdaily? In any event, the mean BMI of people in that lowest quartile was 27.6 in women and 28.0 inmen, that is, they were overweight (conventional threshold: BMI N25.0). Across the three highestquartiles of walking ([1.5–3[, [3–4.5[,≥4.5 km/day), BMI declined to 25.6, 24.7, and 24.2 in women,that is, just slightly above or below the conventional threshold for overweight, but declined to only27.0, 26.9, and 26.4 (all still overweight) inmen.Williams (2011) also found that themore the studyparticipants walked, the less likely they were to imitate the adiposity of their father and/or mother.(Note that we do not say “…the more the study participants walked away from their parents…”!)These findings are stimulating even though they should be viewed with some caution at this pointbecause they are based on partially validated but still self-reported weight, height, walkingintensity, and parental adiposity. A study in which all these variables would be measured iswarranted.

Pigeyre et al. (2011) report on 20-year cross-sectional trends in obesity in the French componentof the WHO-MONICA study (5423 men; 5271 women). In 1986, there seem to have been slightlyfewer obese participants (measured BMI ≥30) among men (15%) than women (15.9%), but theopposite was observed in 2006 (18.3% of men; 17.2% of women). The trend was actually statisticallysignificant only for men. Over the 20-year period the authors also note that the levels of educationand of occupation improved among the study participants. Since there is, however, as expected, astrong inverse association between obesity and education or occupational levels (see Fig. 2 inPigeyre et al. (2011)), they raise the question of whether the improved social status has notattenuated the obesity growth. Their analysis suggests that, indeed, things would have been worsewithout it. These results would need to be reproduced in a longitudinal study, in which the samesubjects can move in and out unemployment, or change income (education does not catch only theyears of school but their social and economic consequences later in life). Nonetheless, beyond itsimperfections, this study points towards some potentially fundamental, overarching determinantsof obesity.

Both papers have in common singling out very prevalent characteristics of the population(walking, education, and employment), which can slow down (and maybe have slowed down) theprogression of obesity in populations. Their interesting ideas are worth testing with more rigorousstudy designs.

References

National Walker's Health Study, 1997. http://www.lbl.gov/Science-Articles/Archive/walkers-study.html Accessed 4 April2011.

Pigeyre, M., Dauchet, L., Simon, C., et al., 2011. Effects of occupational and educational changes on obesity trends in France:the results of the MONICA-france survey 1986-2006. Prev. Med. 52 305–309.

Williams, P.T., 2011. Dose–response relationship between walking and the attenuation of inherited weight. Prev. Med. 52293–299.

atter © 2011 Published by Elsevier Inc.04.001

Alfredo MorabiaCenter for the Biology of Natural Systems, Queens College – CUNY,

163-03 Horace Harding Expressway, Flushing, NY 11365, USA

Michael C. Costanza6 Newbury Close, Rushden, Northamptonshire NN10 0EU, UK

E-mail address: Preventive.Medicine@qc.cuny.edu.

292 This Month in Preventive Medicine