3. Current situation – asthma prevalence
2008- 2010 : 334 millions
Global Burden of Disease Study
2000- 2002: 235 millions
4. Asthma affects both affluent and poor countries
Prevalence of asthma symptoms among 13-14
years old (ISAAC)
Lai CKW, et al. Thorax 2009
5. Uncontrolled asthma
Prevalence of asthma symptoms in the last 12 months
among 18-45 years old in 70 countries (World Health Survey)
To T, et al. BMC Public Health 2012
8. The Burden of Asthma (YLDs)
YLD = years lived with disability
Vos T et al. Lancet 2015; 386:743-800
9. Current situation - summary
no available therapeutic regimens can cure
asthma
rates of deaths due to asthma worldwide have
reduced greatly over the past 25 years, however
they are still high in low income countries
the burden of asthma will continue to be driven
by increasing prevalence
11. Global Burden of Disease Study
2013 (data from 188 countries, comprehensive
methodology for risk factors)
Incomplete methodological approach
Murray C, et al. Lancet published online Sep 11, 2015
12. Global Burden of Disease Study - methodology
Murray C, et al. Lancet published online Sep 11, 2015
13. Global Burden of Disease Study – risk factors
Murray C, et al. Lancet published online Sep 11, 2015
14. Global Burden of Disease Study – risk factors
Murray C, et al. Lancet published online Sep 11, 2015
15. Incomplete methodological approach
Associations are reported between a wide range
of risk factors and childhood asthma in
observational studies which cannot substantiate
causality
Few risk factors have been assessed in primary
prevention studies and these failed because of
bulk selection of patients
16. Incomplete methodological approach
There is no single exposure which seems likely
to cause asthma
Single exposures are invariably contaminated
by other exposures.
17. Risk factors associated with asthma
The hygiene hypothesis (mainly related to atopy)
Obesity/diet/lifestyle
Genetic background
Environmental tobacco smoke and other
pollutants
Atopy
Occupational exposure
Pet ownership
27. Personal and home cleanliness
Weber J, et al. AJRCCM. 2015;191:522-529
Perinatale Asthma Umwelt Langzeit Allergie Studie
(PAULA) birth cohort
28. Smoking increases the risk of asthma by 1.6
King M.E, Mannino D.M, Holguin F. Panminerva Medica 2004; 46: 97-110
29. Postnatal parental smoking increases
the risk of asthma with 20%
Burke H et al. Pediatrics. 2012;129(4):735-44
30. Maternal smoking
Continued maternal smoking during pregnancy was
associated with increased risks of early and
persistent wheezing (OR: 1.24) and asthma (OR:1.65)
den Dekker HT, et al. Chest. 2015;148(3):607-17.
prospective cohort study among 6,007 children
paternal and maternal smoking during pregnancy
(never, first trimester only, continued)
secondhand tobacco smoke exposure during
childhood
31. Maternal smoking – transgenerational effect
Li YF, et al. Chest. 2005;127(4):1232-41
In utero exposure to maternal smoking was
associated with increased risk for asthma diagnosed
in the first 5 years of life, and for persistent asthma
(OR 1.5)
Grandmaternal smoking during the mother's fetal
period was associated with increased asthma risk in
her grandchildren (OR 2.1)
32. Outdoor pollution increases asthma
incidence in adults
Jacquemin B et al. Environ Health Perspect. 2015;123(6):613-216
35. A dietary basis for inflammatory diseases
interactions between
dietary or bacterial
metabolites and
immune cells and
pathways for gut
homeostasis.
Thorburn AN, et al. Immunity 2014;40:834-842.
36. A dietary basis for inflammatory diseases
Palmer DJ, et al. Immunol Allergy Clin N Am 2014;40:825-837.
37. Emerging risk factors
Inference from other preventive strategies
The indoor environment (dampness, ventilation)
Maternal fatty acid status and low vitamin D
during pregnancy
Prenatal exposures to persistent organic
pollutants or stress
Climate change
39. Kunzli N, et al. Am J Respir Crit Care Med. 2006;174(11):1221-8
40. Inference from other preventive strategies
folic acid supplementation in the first trimester
only or first trimester and later had increased
relative odds of asthma
retrospective cohort study of 104,428 children,
born 1996-2005
the association folic acid supplementation and
childhood asthma at ages 4.5-6 years.
folic acid supplementation around conception
helps prevent neural tube defects
Veeranki SP, et al. Epidemiology. 2015 Sep 10. [Epub ahead of print]
42. Asthma risk factors journey
Genetic factors Epigenetic factors
Early window of risk (the prenatal environment)
Acquired risk factors (obesity/diet, pets,
indoor and outdoor pollution/occupational)
The cumulated risk of severe asthma
complex interactions of lung structure and function genes
with environmental exposures
43. Douwes J at el. Eur Respir J. 2008 ;32(3):603-11
Early window of opportunity and
persistent exposure
44. Saskatchewan Rural Cohort Study Group
• 30.6% - early farm living (first year of life) only
• 34.4% - both early and current farm living
• 17.4% had never lived on a farm
• women had a decreased risk for both asthma and
hay fever with an early farm exposure only
• men currently living on a farm without an early
farm exposure had an increased risk for ever
asthma
Early window of opportunity and gender
Rennie DC et al. J Asthma. 2015 Sep 17:1-9. [Epub ahead of print]
45. Q3. What can we do to prevent asthma
2. Address specific risk factors (atopy)
Allergen immunotherapy (AIT)
3.Promote excellence in care
4.Raise awareness at a societal and political level
1. Focus on measures with potential to improve
lung and general health
46. 1. Focus on measures with potential to
improve lung and general health
Reduce smoking
and ETS
Reduce indoor and
outdoor air pollution
and occupational exposures
Improve feto-maternal health
Community level
Reduce social inequalities
Educational level
Reduce childhood obesity;
encourage a diet high in
vegetables and fruit
Promote breastfeeding
Reduce smoking
and ETS
47. AIT in allergic rhinitis prevents asthma
The PAT study
Long term efficacy of AIT
The German real life study
2. Address specific risk factors
48. AIT in allergic rhinitis prevents asthma
The PAT study
Jacobsen L et al. Allergy. 2007;62(8):943-8.
49. AIT in allergic rhinitis prevents asthma
The German real life study
data from German National Health Insurance
cohort of 118,754 patients with AR and without
asthma who had not received AIT in 2005
risk of incident asthma from 2007 to 2012
Schmitt J et al. J Allergy Clin Immunol. 2015 Sep 11. pii: S0091-6749(15)01101-X.
doi: 10.1016/j.jaci.2015.07.038. [Epub ahead of print])
50. The German real life study
only 2.1% received AIT
Schmitt J et al. J Allergy Clin Immunol. 2015 Sep 11. pii: S0091-6749(15)01101-X.
doi: 10.1016/j.jaci.2015.07.038. [Epub ahead of print])
the preventive effect was demonstrated only for the
SC route and was stronger for AIT > 3 years
the risk of incident asthma was significantly less in
patients exposed to AIT (RR = 0.60)
51. 3. Promote excellence in care
High quality guidelines for clinical practice
National Asthma Strategies in countries responding to the Global Asthma
Network Survey
53. Take home messages
A better understanding of the factors that cause
asthma is urgently needed
This knowledge needs to be translated into
public health and primary prevention measures
effective worldwide.
Think outside the box:
WHO: relevant risk factors for the
causation of asthma
WHAT: types of novel primary prevention
strategies developed
HOW: research methods used to provide
the evidence base for their implementation
Editor's Notes
In the GI tract, dietary fiber is primarily digested by
commensal bacteria in the colon, which produces
high concentrations of SCFAs, such as acetate,
propionate, and butyrate. Other metabolites, such
as u-3 fatty acids, succinate, or kynurenic acid,
are directly consumed and absorbed throughout
the GI tract. In addition, metabolites can be
directly absorbed in the small intestine. SCFAs
(mainly acetate) are transported from the gut to the
blood, where they can influence bone marrow and
many cell types throughout the body. Another
major point of intersection is the transfer of metabolites
to the developing fetus. SCFAs are able
to cross the placenta or be delivered via breast
milk, where they can influence gene expression
and the development of the immune system.