Immediate and long term effects of weight reduction in obese people with asthma: randomised controlled study
BMJ 2000; 320 doi: https://doi.org/10.1136/bmj.320.7238.827 (Published 25 March 2000) Cite this as: BMJ 2000;320:827
All rapid responses
Rapid responses are electronic comments to the editor. They enable our users to debate issues raised in articles published on bmj.com. A rapid response is first posted online. If you need the URL (web address) of an individual response, simply click on the response headline and copy the URL from the browser window. A proportion of responses will, after editing, be published online and in the print journal as letters, which are indexed in PubMed. Rapid responses are not indexed in PubMed and they are not journal articles. The BMJ reserves the right to remove responses which are being wilfully misrepresented as published articles or when it is brought to our attention that a response spreads misinformation.
From March 2022, the word limit for rapid responses will be 600 words not including references and author details. We will no longer post responses that exceed this limit.
The word limit for letters selected from posted responses remains 300 words.
Sir,
When two phenomena have been closely correlated through repeated
observations we are often entitled to deduce that such an association is
meaningful and to believe that some previously unknown connection has been
pinpointed in our world. Such is the nature of scientific investigation.
However, this is not always the case and the contemplation of phenomena
can lead in many cases to no new understanding emerging, but merely a
delusion being palmed upon us and accepted as 'new truth'. Association,
inference and correlation do not always mean true causality [1].
Nevertheless, there is no doubt that the spotting and detailed
investigation of correlations is probably the major growing frontier in
science where new ideas do emerge. In some cases, it is also a place where
old ideas can at last find sudden confirmation.
In this example concerning obesity and asthma [2], it is hard to tell
which of these two categories the phenomenon falls into. It could well
turn out to be a case of the latter. While there does seem to be no clear
physiological reason why obesity should cause asthma, maybe if we examine
the causes of obesity, some feature may emerge that is also linked to
repeated attacks of breathlessness [bronchospasm]. Should that prove to be
the case, then new knowledge will certainly have been uncovered.
Obesity is most commonly caused by eating too much food [most notably
fats and complex carbohydrates] or through a lack of exercise; sometimes
both factors combine. Lack of exercise is only of secondary importance and
it is especially the dietary factor that emerges as the main causative
factor in obesity. Regular exercise does improve breathing, but lack of
exercise alone cannot be seriously considered as the main causative factor
in asthma. The question must therefore be asked how dietary behaviour
might lead to bronchospasm? And it is precisely here that we meet up with
some very interesting information. There is a traditional and long-
standing correlation of asthma with the consumption of complex
carbohydrates like cereals, pasta, cakes and bread. But this information
lies beyond the borders of conventional medicine, in the realm of
naturopathy. It is also a basic tenet of nature cure that asthma and the
tendency to it, is relieved by fasting, fruit-only diet, etc.
'...the chief faults in the feeding habits of the mass of people in
this country can be grouped under ten headings...6. the use of too many
starch foods - bread, cakes, biscuits, and cereals of all kinds...10. the
overeating of all foods, regardless of quality. This habit alone can be
said to be responsible for more ill-health and disease in man than all
other bad habits put together....' [3]
'Starches...these are all danger-line foods and while rational diet
should include starches, they should be taken in small quantities only,
and care should be exercised to see that they are derived from whole
grains and not impoverished, as in white flour....a person of sedentary
habits requires very little of this type of food....they should be avoided
in summer, eaten very little in spring and autumn, and only moderately in
winter.' [4]
This paper about asthma and obesity [and Dr Moudgil's letter] serve
as an excellent and timely example, therefore, of why it is so useful for
clinicians to keep an open mind about other healing modalities and be
willing to look beyond the confines of their own field of expertise, when
studying new statistical correlations or to enrich their own thinking on
clinical matters.
Stenius-Aarniala et al seem, therefore, to have unwittingly stumbled
upon some data confirming a basic tenet of nature cure. I presume this was
accidental on their part and that they professed no prior knowledge of
this piece of 'rejected medical knowledge'. It is merely an alternative
perspective on this subject.
regards
Peter Morrell
Sources
[1] see, for example, article and letters of J Hippisley-Cox et al,
Association between teenage pregnancy rates and the age and sex of general
practitioners: cross sectional survey in Trent 1994-7
http://www.bmj.com/cgi/content/full/320/7238/842
[2] Stenius-Aarniala B, Poussa T, Kvarnstrom J, Gronlund EL, Ylikahri
M, Mustajoki P.Immediate and long term effects of weight reduction in
obese people with asthma: randomised controlled study. BMJ 2000;320:827-
32,
http://www.bmj.com/cgi/content/full/320/7238/827
[3] Stanley Lief, 1950, How To Eat for Health, Health for All
Publishing, London, pp.14-17
[4] ibid., p.35; see also Everybody's Guide to Nature Cure by Harry
Benjamin, c.1930
Competing interests: No competing interests
Editor- Obesity is an increasing health problem particularly in the
affluent countries and although the reported association (not necessarily
causal relationship) with asthma is not new, Stenius-Aarniala et al [1]
have appropriately reported the effects of weight reduction in morbidly
obese adults (BMI 30-42) with asthma. Importantly they have also suggested
that, because of the high prevalence of obesity [2], a large number of
patients with asthma will be also be obese.
To highlight the study
findings, in the context of reporting the prevalence of obesity
specifically among subjects with asthma, cross-sectional data collected
during a previously reported community study based in some of the socio-
economically deprived districts in Birmingham (UK) [3] have newly been
analysed.
Of the original 689 study subjects with asthma, 535 (77.6%) were
adults (293 white Europeans, 242 South Asian) within the age group 18 to
59 years. Only 38.5% of these adult subjects had their Body Mass Index
(BMI, kg/m2) within the healthy range (BMI 18.5-24.9) whilst the majority
were either overweight (36.4%, BMI 25-29.9) or obese (19.6%, BMI 30-39.9).
At the extremes, there were 1.7% severely obese (BMI>40) but also 3.6%
underweight (BMI <_18.4. the="the" _="_" predicted="predicted" fev1="fev1" forced="forced" expiratory="expiratory" volume="volume" in="in" first="first" second="second" did="did" not="not" vary="vary" significantly="significantly" range="range" _76.6-79.3="_76.6-79.3" between="between" different="different" categories.="categories." regression="regression" analysis="analysis" these="these" subjects="subjects" showed="showed" that="that" there="there" was="was" also="also" an="an" association="association" bmi="bmi" and="and" both="both" age="age" sex="sex" but="but" with="with" ethnic="ethnic" group.="group." data="data" overall="overall" suggest="suggest" almost="almost" _58="_58" of="of" asthma="asthma" this="this" community="community" were="were" above="above" their="their" ideal="ideal" measurements="measurements" we="we" cannot="cannot" generalize="generalize" as="as" to="to" applicability="applicability" reported="reported" study="study" _1="_1" specifically="specifically" whether="whether" weight="weight" reduction="reduction" would="would" have="have" a="a" similar="similar" impact="impact" all="all" overweight="overweight" well="well" obese="obese" subjects.="subjects." p="p"/> References
1. Stenius-Aarniala B, Poussa T, Kvarnstrom J, Gronlund EL,
Ylikahri M, Mustajoki P.Immediate and long term effects of weight
reduction in obese people with asthma: randomised controlled study. BMJ
2000;320:827-32
2. Seidell JC, Flegal KM. Assessing obesity: classification and
epidemiology. Br Med Bull 1997;53:238-252
3. Moudgil H, Honeybourne D. Differences in asthma management
between white European and Indain subcontinent ethnic groups living in
socioeconomically deprived areas in the Birmingham (UK) conurbation.
Thorax 1998;53:490-94.
H MOUDGIL
Consultant Physician
Princess Royal Hospital, Telford TF6 6TF
Email h.moudgil@thedoctor.co.uk
No competing / conflicting interest
Competing interests: No competing interests
Sex difference in the obesity-asthma link
EDITOR - A prospective study of women recently found that fatness was
associated with an increased risk of incident asthma[1] and in cross-
sectional studies of adolescents and adults the positive association
between fatness and asthma has consistently been observed in females but
not in males.[2][3][4] I was therefore interested to note that the
majority of participants in the trial by Stenius-Aarniala and colleagues
were women (13/19 in the intervention group and 16/19 in the control
group).[5] Although there were few men in the trial, it would be
interesting to know whether their asthma improved following the
intervention, or whether the beneficial effects of weight reduction on
asthma severity were only seen in the women.
1. Camargo CA, Weiss ST, Zhang S, Willett WC, Speizer FE. Prospective
study of body mass index, weight change and risk of adult-onset asthma in
women. Arch Intern Med 1999; 159: 2582-88.
2. Huang S-L, Shiao G-M, Chou P. Association between body mass index
and allergy in teenage girls in Taiwan. Clin Exp Allergy 1999; 29: 323-9.
3. Shaheen SO, Sterne JAC, Montgomery SM, Azima H. Birth weight, body
mass index and asthma in young adults. Thorax 1999; 54: 396-402.
4. Chen Y, Dales R, Krewski D, Breithaupt K. Increased effects of
smoking and obesity on asthma among female Canadians: the National
Population Health Survey, 1994-1995. Am J Epidemiol 1999; 150: 255-62.
5. Stenius-Aarniala B, Poussa T, Kvarnstrom J, Gronlund E-L, Ylikahri
M, Mustajoki P. Immediate and long term effects of weight reduction in
obese people with asthma: randomised controlled study. BMJ 2000; 320: 827-
32.
Seif Shaheen
Senior Lecturer in Clinical Epidemiology
Department of Public Health Sciences,
Guy's, King's and St Thomas' School of Medicine,
King's College, London,
Capital House,
42, Weston Street,
London, SE1 3QD
I have no competing interests.
Competing interests: No competing interests