Long term effects of air pollution on health.

Peter Burney.

King’s College London

Breathlessness by night or day by annual mean PM10 (Sepaldia)

• Selected symptoms associated with measures of air pollution

• Some correlations work out better than others

Proportion of the non-smoking population with FVC < 70% by TSP (NHANES)

• Continuous increase in poor lung function as particulate levels rise.

• Adjusted for age, height, sex, race, obesity, occupation, temperature, income and region

The Meaning of Chronic Morbidity

• Repeated acute effects?

• Change in susceptibility?

• Irreversible changes?

1

1.1

1.2

1.3

1.4R

elat

ive

Ris

k

20 40 60 80 100 120

PM10 cutoff g.m-3

Risk of developing symptoms of airways obstructive diseaseaccording to hours/year exposure to different levels of PM10

250hrs

500hrs

1000hrs

2500hrs

5000hrs

0

10

20

30

40

Pre

vale

nce

of r

espi

rato

ry s

ympt

oms

<30 30-60 >60

SMOKE (g/m3)

Smoke and symptoms in schoolgirls, UK 1981

3 or more

1 or more

-30

-20

-10

0

10

Net

cha

nge

in R

espi

rato

ry S

ympt

oms

(%)

0 -1.4 -35.9 -49.8 -58.9

Smoke Change (g/m3)

Longitudinal analysis of symptoms and smoke pollutionin British schoolgirls 1973-1974 (Melia et al. 1981)

Changes in lung function in different communities (Tashkin 1994)

Relative decline in FEV1 (ml)

TSP (mg/m3) MEN WOMEN

Lancaster 85 0 0Long Beach 101 -18.4* -15.6**Glendora 133 -26.5** -16.2**

Adjusted for age, height, initial FEV1, allergy and smoking*p<0.01; **p<0.001

Differences in lung function growth between ‘polluted’ and ‘unpolluted’ areas

(from Jedrychowski, et al. 1999)

Boys (95% CI) Girls (95% CI) FVC (ml/yr) -101 (-206, 4)+ -125 (-231,-19)*

FEV1 (ml/yr) -154 (-264,-44)* -142 (-259,-25)*

+p=0.09 *p=0.02

Factors predicting adult respiratory disease in the 1946 national birth cohort (Mann et al, 1992)

Wheeze/Asthma

LowerRespiratoryDisease

Phlegm PEFR

EARLY LIFE FACTORS

LRI before 2 yrs 6.1 4.1 4.7 0.8Bronchitis inparents 6.6 3.4 6.2 1.9Poor homeconditions 10.0 6.2 12.5 8.8Pollution 0-2 yrs 3.8 3.1 0.5 0.1Pollution 2-11 yrs 4.5 3.2 3.1 0

LATER FACTORS

Smoking 20.2 9.0 23.5 0Asthma - 2.8 4.4 0

SMR from bronchitis related to area based infant mortality from LRTI

• Area SMR from bronchitis is associated with infant mortality from pneumonia 70years earlier.

0

1

2

3A

dult

FE

V1

(litr

es)

<5.5 -6.5 -7.5 -8.5 -9.5 >9.5

Birth weight (lbs)

Relation of adult FEV1 to Birthweightand smoking(Barker et al., 1991)

Never smokers

Ex-smokers

current

0

0.5

1

1.5

2

2.5

3

Adu

lt F

EV

1 (l

itres

)

<5.5 -6.5 -7.5 -8.5 -9.5 >9.5

Birth weight (lbs)

Relation of adult FEV1 to birthweight andbroncuitis or pneumonia in infancy

(Barker et al. 1991)

ALRI in infancy

No ALRI in infancy

0

20

40

%

LOW HIGH

Air Pollution

Chest disease before 2 years by air pollution level (1946 birth cohort)

Possible causes of inconsistency

• Various outcomes• Various exposures• Modifying factors• Measurement errors

• Bronchitis• COPD• Allergy• Asthma• Cancer• Early infection• Premature birth

Possible causes of inconsistency

• Various outcomes• Various exposures• Modifying factors• Measurement errors

• Particles • SO2• NO2• Oxidants• ‘Traffic’• Diesel

Lorry traffic affects infant lung disease in

metropolitan but not urban or rural areas (Ciccone et al., 1998)

Effect of lorry traffic on early respiratory disease

0

0.5

1

1.5

Daily lorry transit

Rel

ativ

e ris

k

Urban/rural

Metropolitan

Effect of supplementing cyclists with antioxidants on the respiratory response to ozone (from

Grievink et al. 1998)

Treatment Control Treatment effect

Mean (sem) Mean Sem Difference (95% CI)

FVC 0.25 0.24 -1.83 0.49 2.08 1.31,2.85

FEV1 -0.20 0.60 -1.86 0.49 1.66 0.62,2.70

PEF 1.48 3.04 -5.35 2.03 6.83 3.17,10.49

MMEF -0.51 0.93 -0.93 0.94 0.42 -1.38,2.22

Prospects

•The evidence is currently descriptive.•The evidence is reported inconsistently.•There is likely to be reporting bias.•Much of the data refers to pollution patterns that are now largely historic.

ECRHS II

• A follow-up of subjects studied in ECRHS I

• A study of many different protocols linked to studying aetiology and prognosis

• Principal outcomes relate to atopy, asthma, lung function and bronchial hyper-responsiveness

• Some specific protocols on air pollution

ECRHS II centres

ECRHS II pollution protocols

• Historic review of air pollution data• Measurement of PM2.5 in all centres• Analysis of PM2.5 for metal content• Measurement of dust mite allergen from beds• Measurement of NO2 from kitchens, outside

kitchen windows and at central monitor in selected centres

NO2 arithmetic annual mean 1999

29

32

27 28

303029

27252524

1817

10

34 34 35

50 50 50 51 52

66

0

10

20

30

40

50

60

70

GALDAKAO

ALBACETE

HUELVA

DundeeTar

tuPorto

GOTEBORG

BASEL

BARCELONA

Vienna

Montp

ellie

r

Cambrid

ge

GELEEN

Hamburg

GRENOBLE

BERGEN

PAVIA

ANTWERP

TURIN

Coimbra

PARIS

Athen

s

Dublin

g/m3

Traffic stations

Background stations

PM 10 annual arithmetic mean 1999

29

13

16

21 22 2223

25

32

42

49

2828

0

10

20

30

40

50

60

g/m3

Background stations

Traffic stations

ECRHS II

Analysis principally relates to the natural history (incidence, remission and modification of disease over

time) of asthma, atopy, lung function, and airway responsiveness.

ECRHS II

The major strengths of the study are its size, the diversity of the environments studied, the extent of

the potential confounders being assessed.