Estimate-riddled study concludes passive smoking causes 1 per cent of deaths globally

Completely disregarding the tenuous link between risk and causation, The Lancet has published a study telling us that passive smoking causes 1 per cent of deaths globally, all without one single identified case. I imagine they do it by calculating the excess of exposed over non-exposed people in 192 countries, using indicators such as cotinine in hair to estimate exposure levels. (Is this any more subtle than saying children are dying from the effects of secondary smoke simply because their parents smoke?) The data in the study were taken from 2004.

The study itself is hidden behind a paywall [late edit: no payment required, registration is free], but appears to start with estimates of exposure, and proceed to conclude that the exposure caused death in thousands of people, including children, globally. Getting at the actual reasoning would be interesting, but it doesn't look subtle. Funding is from the Swedish government and Bloomberg Philanthophites.

The Independent's report is the most detailed, with such beauties as this:

The harm done by passive smoking has been known for decades but it is only in the last 10 years that the scale of the damage – and ways to prevent it – have become clear. Controversy has surrounded the issue because of the disproportionate risks of passive smoking. A non-smoker who lives with a person who smokes 20 cigarettes a day has third of the risk to health of their partner, even though they are actually exposed to only 1 per cent of the smoke, equivalent to one cigarette every five days.

How can 1 per cent of the exposure amount to 33 per cent of the risk?

The scale of the risk has met with disbelief and scientists have struggled to convey why it is so high. Evidence shows that the effect on the blood of toxins in tobacco smoke peaks at low levels of exposure. The toxins increase the stickiness of the blood (the tendency of the platelets to aggregate) and inflame the arteries, increasing the risk of thrombosis, a blood clot forming that that triggers a heart attack.

Oh, for goodness sake ... is this why only studies on lifetime exposure get anywhere close to a positive correlation between exposure and mortality?

Part of the agenda behind all of this can be found in the Caledonian Mercury's report. Sheila Duffy of ASH Scotland is quoted, inevitably homing in on the reported damage to children.

Although we have made great progress in Scotland by making public places smoke-free, exposure to this poisonous substance is still commonplace in homes and cars. Children can be particularly badly affected by exposure to tobacco smoke, increasing their risk of developing respiratory problems and other conditions.

In Scotland, around 300,000 pre-teen children live with at least one parent who smokes. Because we know second-hand smoke can cause so many avoidable health problems, reducing exposure must be a priority. We need to see much more work done to raise the awareness of harm that tobacco smoke causes, and a positive campaign to highlight the benefits to families of introducing smoke-free homes and cars in Scotland and to help people understand how to protect themselves and their children effectively.

So it gives ASH Scotland ammunition to push forward its agenda to 'intervene' in people's homes and cars in order to reduce the second-hand smoke exposure of children. Not unexpected. And on the world stage, from the study authors:

Prompt attention is needed to dispel the myth that developing countries can wait to deal with tobacco-related diseases until they have dealt with infectious diseases. Together, tobacco smoke and infections lead to substantial, avoidable mortality and loss of active life-years of children

Clearly the study authors want to divert health money to tobacco control, rather than spend more on infectious diseases.

I don't see the logic under any circumstances of prioritising 'unhealthy' lifestyle choices above treating and preventing communicable diseases. This study seems designed for no other purpose than to justify tobacco control activities at all levels by claiming that children are dying as a direct result of tobacco smoke (without being able to identify who they are).