Drop in child asthma. Vindication for smoking ban?

[biotechpete]

I was not entirely convinced on reading the BBC article so in an attempt to shed some light on the actual data, I can tell from the published article that the authors obtained data from a national database on hospital admissions.

 

They looked for children 0-14, divided into 0-4 and 5-14; to reflect their change in home exposure when attending school. They counted the actual number of admissions to hospital (1st April 2002 - 30th Nov 2010), in England, for children in those age ranges with a primary cause of asthma.

The data were divided into roughly 6780 equal geographical areas containing an average of 7200 people, based on an ONS statistical framework. Based on which of the 6780 areas they resided in, the children were assigned to each of 5 socio-economic bands, rural/urban, and English region.

The data were then analysed to give an underlying trend of asthma admissions before July 2007. The model then compares the change in actual admissions vs what the trend in admissions predicted if no smoking ban had come into place. Sub-group analysis was conducted to compare the effect of age, gender, socio-economic status, urban vs rural and region.

 

There were 217 381 total hospital admissions during the period studied 2002-2010. Near enough 50% were in each 0-4 and 5-14 age group. There were more boys (~65%) more urban (~85%) and more socio-economically deprived admissions (1.8x more in most deprived, dropping to 1.5, 1.3 & 1.1x for increasing wealth compared to least deprived. Increase in admissions per region (compared to London) were highest 1.58x in the North West. Yorkshire & Humber region was 1.16x, 4th of 9 regions with the lowest 0.95 x in East of England. Interestingly, the NW is also the region with the highest rate of smoking related lung diseases.

 

After implementation of the ban, there was an actual drop of 8.9% in hospital admissions and a change in trend of -3.4% so a net immediate 12.3 % reduction in the first year. But there were no significant effect of age, gender, socioeconomic status, urban vs rural or region.

 

These stats are similar to the effect of smoking bans at different times and in different places to the immediate drop in asthma exacerbations in Scotland (-18%) and Arizona (-22%) and also to similar laws in Toronto and Kentucky.

 

Health survey data from the time shows the effect of the smoking ban was to immediately reduce smoke exposure in children and increase the number of smoke free homes and cars.

 

The statistics used assume one linear trend before the law and a different one after. It cannot distinguish the effect of the law from other factors such as therapies or change in asthma management in the NHS, however there were no significant changes in either of these factors at the time.

 

Personally, I find the data quite compelling.

[chem1st]

They brought in the smoking ban then the greater depression began!

 

Coincidence?

[biotechpete]

Look Ive skimmed thriugh the article again the numbers are down to the smoking ban and only the smoking ban, not down to lower amounts of particles in the air, change in farming practices, misdiagnosis or better treatment that will affect numbers it's JUST the smoking ban. If me and my aunt fanny (aged 134 3/4) agree on this, so should you or remain a crackpot.

 

All previous studies I've read and or taken part in as an asthma sufferer over that last 33 years are now completely disregarded.

 

The authors do address these points.

Particles in the air: There was no difference between urban/rural. Most of the effect of air pollution is seasonal and the model adjusted for this and

thus implicitly account for changes in admissions due to seasonal changes in air pollution.

Misdiagnosis: Diagnoses were based on the "international classification of disease" and there were no concurrent changes to guidelines/policy on diagnosis.

Better treatment: New drugs (leukotriene antagonists) were introduced in the study period prior to the ban, but prescribing rates increased gradually and are still very low. It is not thought that this might cause the sudden drop after July 2007.

Farming: This wasn't covered but similar to treatment, that would have to be a pretty sudden and drastic change in farming practices over the time period.

[gym_rat]

I was not entirely convinced on reading the BBC article so in an attempt to shed some light on the actual data, I can tell from the published article that the authors obtained data from a national database on hospital admissions.

 

They looked for children 0-14, divided into 0-4 and 5-14; to reflect their change in home exposure when attending school. They counted the actual number of admissions to hospital (1st April 2002 - 30th Nov 2010), in England, for children in those age ranges with a primary cause of asthma.

The data were divided into roughly 6780 equal geographical areas containing an average of 7200 people, based on an ONS statistical framework. Based on which of the 6780 areas they resided in, the children were assigned to each of 5 socio-economic bands, rural/urban, and English region.

The data were then analysed to give an underlying trend of asthma admissions before July 2007. The model then compares the change in actual admissions vs what the trend in admissions predicted if no smoking ban had come into place. Sub-group analysis was conducted to compare the effect of age, gender, socio-economic status, urban vs rural and region.

 

There were 217 381 total hospital admissions during the period studied 2002-2010. Near enough 50% were in each 0-4 and 5-14 age group. There were more boys (~65%) more urban (~85%) and more socio-economically deprived admissions (1.8x more in most deprived, dropping to 1.5, 1.3 & 1.1x for increasing wealth compared to least deprived. Increase in admissions per region (compared to London) were highest 1.58x in the North West. Yorkshire & Humber region was 1.16x, 4th of 9 regions with the lowest 0.95 x in East of England. Interestingly, the NW is also the region with the highest rate of smoking related lung diseases.

 

After implementation of the ban, there was an actual drop of 8.9% in hospital admissions and a change in trend of -3.4% so a net immediate 12.3 % reduction in the first year. But there were no significant effect of age, gender, socioeconomic status, urban vs rural or region.

 

These stats are similar to the effect of smoking bans at different times and in different places to the immediate drop in asthma exacerbations in Scotland (-18%) and Arizona (-22%) and also to similar laws in Toronto and Kentucky.

 

Health survey data from the time shows the effect of the smoking ban was to immediately reduce smoke exposure in children and increase the number of smoke free homes and cars.

 

The statistics used assume one linear trend before the law and a different one after. It cannot distinguish the effect of the law from other factors such as therapies or change in asthma management in the NHS, however there were no significant changes in either of these factors at the time.

 

Personally, I find the data quite compelling.

 

now, when you put it like that - well done the smoking ban

 

 

 

 

still based on a guess though

[Olive]

 

Health survey data from the time shows the effect of the smoking ban was to immediately reduce smoke exposure in children and increase the number of smoke free homes and cars.

 

The statistics used assume one linear trend before the law and a different one after. It cannot distinguish the effect of the law from other factors such as therapies or change in asthma management in the NHS, however there were no significant changes in either of these factors at the time.

 

Personally, I find the data quite compelling.

 

Thanks for this Pete, very informative. I agree, compelling figures, but there's a large part of the story missing, which the article just ignores.

 

They are suggesting that the drop in asthma admissions is due to people not smoking at home. The data you highlight backs this up and includes cars in the equation.

 

This makes sense - homes and cars, both places kids are likely to be exposed to smoke.

 

But the smoking ban does not apply to homes and cars.

 

I can totally see that the smoking ban has probably urged people on to give up smoking, therefore there would be an indirect link. But there's no mention of this possibility (or why the ban in public places might have stopped people smoking in the home).

 

That would be a more interesting story.

[biotechpete]

The article and data is showing a decrease in asthma hospital admissions that's all. People seem to be reading it as an overall decline in asthma rates due to the smoking bans which is not what it is stating.

 

It's not what they were testing but the authors do suggest by the tone of the article that there might be a link. I.e. they quote literature connecting the incidence of asthma to second hand smoke exposure in children and say that the effect of the smoking ban has directly decreased the level of childhood smoke exposure through increasing the number of smoke free homes and cars.

 

They stop short of making a direct link between hospital admissions of children for asthma exacerbations and the actual rates of disease incidence but I suppose it is one explanation for the drop in admissions. A follow up in 4 years might tell us that; since if the level of admissions in the 0-4 age range drops significantly lower than 50% of the total then this would suggest a reduction in childhood asthma post ban.

[Olive]

It's not what they were testing but the authors do suggest by the tone of the article that there might be a link. I.e. they quote literature connecting the incidence of asthma to second hand smoke exposure in children and say that the effect of the smoking ban has directly decreased the level of childhood smoke exposure through increasing the number of smoke free homes and cars.

 

This is the problem with the article - they make no attempt to explain why (not even conjecture) the smoking ban - in public places - has increased smoking in private. Therefore the narrative doesn't make any sense, and that's what's so annoying.

[biotechpete]

Thanks for this Pete, very informative. I agree, compelling figures, but there's a large part of the story missing, which the article just ignores.

 

They are suggesting that the drop in asthma admissions is due to people not smoking at home. The data you highlight backs this up and includes cars in the equation.

 

This makes sense - homes and cars, both places kids are likely to be exposed to smoke.

 

But the smoking ban does not apply to homes and cars.

 

I can totally see that the smoking ban has probably urged people on to give up smoking, therefore there would be an indirect link. But there's no mention of this possibility (or why the ban in public places might have stopped people smoking in the home).

 

That would be a more interesting story.

 

They do touch on this in the paper. They quote some studies done here and in other countries after smoking bans showing immediate drops in the levels of cotinine in childrens' urine (a metabolite of nicotine). They also quote health survey data from England (published in an open access journal) for the homes and cars thing:

Lee JT, Glantz SA, Millett C. Effect of smokefree legislation on adult smoking behaviour in England in the 18 months following implementation. PLoS ONE. 2011;6(6):e20933

 

What's weird about that paper is that is shows no overall increase in the overall trend towards cessation. But there were many more quit attempts, and importantly smoking in the home reduced significantly. I guess that perhaps the smoking ban and the media coverage of it has made more people aware of the risks of smoking in the home and perhaps particularly the effect of passive smoking on children. It seems as though there has been a social shift towards is being less acceptable to smoke in confined spaces.

[Fallow]

I do not smoke. I do not however believe that the reduction is due to banning smoking in public buildings. It is to do with the green laws that have been introduced. Emissions from petrol is way down as are industrial emissions. Smoking puts much fewer toxins into the air than any of these.

The continuing price rises and restricting of places that people are allowed to smoke is causing premature death through obesity.

[tinfoilhat]

The authors do address these points.

Particles in the air: There was no difference between urban/rural. Most of the effect of air pollution is seasonal and the model adjusted for this and

 

Misdiagnosis: Diagnoses were based on the "international classification of disease" and there were no concurrent changes to guidelines/policy on diagnosis.

Better treatment: New drugs (leukotriene antagonists) were introduced in the study period prior to the ban, but prescribing rates increased gradually and are still very low. It is not thought that this might cause the sudden drop after July 2007.

Farming: This wasn't covered but similar to treatment, that would have to be a pretty sudden and drastic change in farming practices over the time period.

 

Some really interesting points here, as the your post above. Thankyou for taking the time to pad it out. Says so much more than a bbc article !

 

A couple of points to add on though:

 

1. The study is over 8 years - half of which saw the country hit hard economically - is this factored in considering socio-economically deprived admissions. I know I'm wandering to chem1sts favourite area but is poor housing etcfactored in ?

2. Although there haven't been any new drugs widely available, there have been constant changes on how to take the current ones (1st 2 puffs 4 x a day, then 4 puffs twice a day, use the stupid plastic bubble thing on an inhaler that sort of thing). Is that factored in or are asthma clinics wasting their time ?