Research of the week
Interventions to promote walking
BMJ 2007; 334: 1,204
Half an hour of moderate physical exercise - for example moderately paced walking - on most days is known to provide physical benefit.
This systematic review of 48 trials looked at the best way of promoting walking. Successful interventions were those targeted at groups already motivated to change, with particular success noted among the most sedentary.
Interventions can increase the amount walked by up to 30-60 minutes per week, at least in the short term, with some studies showing objective as well as subjective health gains.
It was not clear who should provide the advice - perhaps we will need to delegate.
Reduction in deaths from CHD in the USA
N Engl J Med 2007; 356: 2,388-98
If you have ever wondered whether health promotion actually works, this study should encourage you.
In the US between 1980 and 2000 the rate of death per 100,000 from CHD halved from 542.9 to 260.8 for men and from 263.3 to 134.4 for women. The authors conclude that about half this improvement is due to medical interventions, such as secondary prevention post-MI, revascularisation and heart failure treatment, and half due to reduction in risk factors, such as lowering cholesterol, better BP control and smoking cessation.
This is excellent news - slightly offset by the fact that increasing diabetes and obesity had had a small negative effect on the statistics. Weight control next for quality points, perhaps?
Benefits of breatsfeeding
Arch Dis Childhood 2007; 92: 483-5
The authors examined systematic reviews and meta-analyses in England and Wales with an overall study population of 596,122 women. They estimated that 33,100 cases of asthma, 2,655 of coeliac disease and 13,639 of obesity would be prevented over seven to nine years if all mothers breastfed. The authors suggested that if this were presented as the number of cases prevented by eliminating 'no breastfeeding' as a risk factor, or population impact number, the general public would find it easier to understand.
Perhaps, but what about GPs?
Weight, menopause, calcium and vitamin D
Arch Int Med 2007; 167: 893-902
Following anecdotal evidence that calcium and vitamin D might have an impact on the weight gain many women experience post menopause, the authors of this US study recruited 36,282 postmenopausal women aged 50-79 who were already taking part in the Women's Health Initiative, and randomised them to take either 1,000mg calcium plus 400IU vitamin D daily, or placebo. After seven years, there was a small but significant reduction in expected weight gain in the treated group, particularly those who had previously had a low-calcium diet.
Physiotherapist-directed exercise for back pain
Ann Int Med 2007; 146: 787-96
In this Australian randomised, placebo-controlled trial, 259 people with back pain were randomised to receive either 12 physiotherapist-directed exercise sessions or sham exercise sessions and three physio-directed advice or sham advice sessions over six weeks. Outcomes were pain, function and global perceived effect.
Exercise and advice were slightly more effective than placebo at six weeks, with the greatest effect when they were combined. At 12 weeks there was a small but significant effect on function only. This confirms my suspicions that back pain is fairly resistant to any intervention.
Formula estimation of GFR
BMJ 2007; 334: 1,198-1,200
This analysis tends to corroborate the view that large-scale estimation of glomerular filtration rates is tending to medicalise people who seem healthy. The authors compared eGFR with GFR measured by isotopic methods and found poor correlation at higher levels. This could potentially create difficulties for people in obtaining life insurance, for instance, and overload renal clinics with anxious people who do not need treatment.
Lack of standardisation of testing is also highlighted, for example, a meat-rich meal can raise creatinine significantly.
The conclusion is that our present eGFR system lacks a good scientific basis and more research is needed to ensure it is effective.
Dr Glenesk is a GP in Aberdeen and a member of our team of regular research reviewers.
The quick study
- CHD deaths halved in the US between 1980 and 2000 due to medical intervention.
- Breastfeeding can reduce incidences of asthma, coeliac disease and obesity.
- Menopausal weight gain is reduced by treating with calcium and vitamin D.
- Back pain is slightly improved by physiotherapist-led advice and exercise.
- eGFR calculations may be medicalising healthy patients and more research is needed.