HOW do we persuade more adults to take part in cancer screening?

It is a question that is preoccupying public health bosses amid declines in uptake for both breast and cervical screening in Scotland, and elsewhere in the UK. Figures last week showed that three in 10 eligible women in Scotland are missing breast screening, and that attendance has "fallen consistently" for a decade.

The percentage of women in Scotland attending for smear tests is also short - 73 per cent compared to an 80% minimum target.

READ MORE: Routine bowel screening of all over-50s should be reconsidered, say experts 

Only bowel cancer screening is at record participation - 64% - following the introduction of the simpler FIT test, which means people only have to return one stool sample instead of three.

A report for the NHS in England this week by former national cancer director Professor Sir Mike Richards advised running screening clinics at weekends and evenings, and in mobile units such as supermarket car parks, in effort to boost uptake.

There is no doubt that screening programmes are a useful tool for early detection, but they are also expensive because of the huge extra workload generated for the NHS from false positives.

For example, of the 3.1% of 'positive' bowel cancer tests generated by the new FIT screen, only 5.2% actually turned out to be bowel cancer.

In exchange for hundreds of additional colonoscopies, the new screening tool detected 12 cases of bowel cancer per 10,000 tests compared to 11 per 10,000 using the old system.

READ MORE: NHS 'should consider axing routine breast screening', says expert 

A recent international review recommended targeted bowel screening instead to over-50s whose risk of developing the disease was an above average 3% or more. They argued it would boost uptake because those targeted would know they were in danger, while limiting the waiting times bottleneck for follow-up tests.

The problem with screening is that, once introduced, any attempts to make it more efficient are instantly politicised as 'cutbacks'. Even if the science makes sense.

And here's the other thing: screening uptake is lowest among those most likely to get cancer - poor people.

Poverty is intertwined with stress, and stress is major driver for cancer-causing habits such as smoking, overeating leading to obesity, excess alcohol consumption, and lack of exercise.

No amount of screening can compensate for Scotland's increasing poverty and widening inequality.

Meaningful employment on a living wage, decent welfare support for those who need it, and an urban environment that promoted walking and cycling would do more to improve the nation's health.

READ MORE: New mothers in Lanarkshire urged to go for smear tests 

But instead we have austerity, zero hours contracts and rampant opposition to giving up roadspace to cycleways. The Scottish Government has also dragged its heels on increased child benefit for the poorest.

Investment in screening should not be at the expense of public health interventions which could do more, in the long-run, to prevent disease.