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Milk intake and risk of mortality and fractures in women and men: cohort studies

October 29, 2014 Comments off

Milk intake and risk of mortality and fractures in women and men: cohort studies
Source: British Medical Journal

Objective
To examine whether high milk consumption is associated with mortality and fractures in women and men.

Design
Cohort studies.

Setting
Three counties in central Sweden.

Participants
Two large Swedish cohorts, one with 61 433 women (39-74 years at baseline 1987-90) and one with 45 339 men (45-79 years at baseline 1997), were administered food frequency questionnaires. The women responded to a second food frequency questionnaire in 1997.

Main outcome measure
Multivariable survival models were applied to determine the association between milk consumption and time to mortality or fracture.

Results
During a mean follow-up of 20.1 years, 15 541 women died and 17 252 had a fracture, of whom 4259 had a hip fracture. In the male cohort with a mean follow-up of 11.2 years, 10 112 men died and 5066 had a fracture, with 1166 hip fracture cases. In women the adjusted mortality hazard ratio for three or more glasses of milk a day compared with less than one glass a day was 1.93 (95% confidence interval 1.80 to 2.06). For every glass of milk, the adjusted hazard ratio of all cause mortality was 1.15 (1.13 to 1.17) in women and 1.03 (1.01 to 1.04) in men. For every glass of milk in women no reduction was observed in fracture risk with higher milk consumption for any fracture (1.02, 1.00 to 1.04) or for hip fracture (1.09, 1.05 to 1.13). The corresponding adjusted hazard ratios in men were 1.01 (0.99 to 1.03) and 1.03 (0.99 to 1.07). In subsamples of two additional cohorts, one in males and one in females, a positive association was seen between milk intake and both urine 8-iso-PGF2α (a biomarker of oxidative stress) and serum interleukin 6 (a main inflammatory biomarker).

Conclusions
High milk intake was associated with higher mortality in one cohort of women and in another cohort of men, and with higher fracture incidence in women. Given the observational study designs with the inherent possibility of residual confounding and reverse causation phenomena, a cautious interpretation of the results is recommended.

See also: Editorial – Milk and Mortality

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Mild hypertension in people at low risk

September 22, 2014 Comments off

Mild hypertension in people at low risk
Source: British Medical Journal

Summary box

  • Clinical context—Up to 40% of adults worldwide have hypertension, complications of which may account for up to 9.4 million deaths annually from cardiovascular disease
  • Diagnostic change—Recommendations for drug treatment have decreased from diastolic pressure of >115 mm Hg to ≥140/90 mm Hg. A new category, prehypertension (120/80-139/89 mm Hg), has also been introduced
  • Rationale for change—Patients with even mildly raised blood pressure may have increased cardiovascular risk
  • Leap of faith—Lowering threshold blood pressures will lead to increased diagnosis and treatment, which will decrease mortality
  • Impact on prevalence—22% of adults worldwide have mild hypertension (systolic pressure 140-159 mm Hg) and 13.5% have a systolic pressure ≥160 mm Hg
  • Evidence of overdiagnosis—Use of a uniform threshold (140 mm Hg) to mark hypertension risk ignores evidence that risk varies by individual and includes many people who will not benefit from drug treatment
  • Harms from overdiagnosis—Studies suggest over half of people with mild hypertension are treated with drugs even though this approach has not been proved to decrease mortality or morbidity. Overemphasis on drug treatment risks adverse effects, such as increased risk of falls, and misses opportunities to modify individual lifestyle choices and tackle lifestyle factors at a public health level
  • Limitations of evidence — Lack of randomised trials that use hard outcomes and compare drugs with lifestyle interventions and placebo in patients with mild hypertension
  • Conclusion—Lowering definitions of hypertension has led to identification and drug treatment of larger populations of patients despite lack of evidence that drugs reduce morbidity or mortality

Changes in antidepressant use by young people and suicidal behavior after FDA warnings and media coverage: quasi-experimental study

June 20, 2014 Comments off

Changes in antidepressant use by young people and suicidal behavior after FDA warnings and media coverage: quasi-experimental study
Source: British Medical Journal

Objective
To investigate if the widely publicized warnings in 2003 from the US Food and Drug Administration about a possible increased risk of suicidality with antidepressant use in young people were associated with changes in antidepressant use, suicide attempts, and completed suicides among young people.

Design
Quasi-experimental study assessing changes in outcomes after the warnings, controlling for pre-existing trends.

Setting
Automated healthcare claims data (2000-10) derived from the virtual data warehouse of 11 health plans in the US Mental Health Research Network.

Participants
Study cohorts included adolescents (around 1.1 million), young adults (around 1.4 million), and adults (around 5 million).

Main outcome measures
Rates of antidepressant dispensings, psychotropic drug poisonings (a validated proxy for suicide attempts), and completed suicides.

Results
Trends in antidepressant use and poisonings changed abruptly after the warnings. In the second year after the warnings, relative changes in antidepressant use were −31.0% (95% confidence interval −33.0% to −29.0%) among adolescents, −24.3% (−25.4% to −23.2%) among young adults, and −14.5% (−16.0% to −12.9%) among adults. These reflected absolute reductions of 696, 1216, and 1621 dispensings per 100 000 people among adolescents, young adults, and adults, respectively. Simultaneously, there were significant, relative increases in psychotropic drug poisonings in adolescents (21.7%, 95% confidence interval 4.9% to 38.5%) and young adults (33.7%, 26.9% to 40.4%) but not among adults (5.2%, −6.5% to 16.9%). These reflected absolute increases of 2 and 4 poisonings per 100 000 people among adolescents and young adults, respectively (approximately 77 additional poisonings in our cohort of 2.5 million young people). Completed suicides did not change for any age group.

Conclusions
Safety warnings about antidepressants and widespread media coverage decreased antidepressant use, and there were simultaneous increases in suicide attempts among young people. It is essential to monitor and reduce possible unintended consequences of FDA warnings and media reporting.

Helmet therapy in infants with positional skull deformation: randomised controlled trial

May 2, 2014 Comments off

Helmet therapy in infants with positional skull deformation: randomised controlled trial
Source: British Medical Journal

Objective
To determine the effectiveness of helmet therapy for positional skull deformation compared with the natural course of the condition in infants aged 5-6 months.

Design
Pragmatic, single blinded, randomised controlled trial (HEADS, HElmet therapy Assessment in Deformed Skulls) nested in a prospective cohort study.

Setting
29 paediatric physiotherapy practices; helmet therapy was administered at four specialised centres.

Participants
84 infants aged 5 to 6 months with moderate to severe skull deformation, who were born after 36 weeks of gestation and had no muscular torticollis, craniosynostosis, or dysmorphic features. Participants were randomly assigned to helmet therapy (n=42) or to natural course of the condition (n=42) according to a randomisation plan with blocks of eight.

Interventions
Six months of helmet therapy compared with the natural course of skull deformation. In both trial arms parents were asked to avoid any (additional) treatment for the skull deformation.

Main outcome measures
The primary outcome was change in skull shape from baseline to 24 months of age assessed using plagiocephalometry (anthropometric measurement instrument). Change scores for plagiocephaly (oblique diameter difference index) and brachycephaly (cranioproportional index) were each included in an analysis of covariance, using baseline values as the covariate. Secondary outcomes were ear deviation, facial asymmetry, occipital lift, and motor development in the infant, quality of life (infant and parent measures), and parental satisfaction and anxiety. Baseline measurements were performed in infants aged between 5 and 6 months, with follow-up measurements at 8, 12, and 24 months. Primary outcome assessment at 24 months was blinded.

Results
The change score for both plagiocephaly and brachycephaly was equal between the helmet therapy and natural course groups, with a mean difference of −0.2 (95% confidence interval −1.6 to 1.2, P=0.80) and 0.2 (−1.7 to 2.2, P=0.81), respectively. Full recovery was achieved in 10 of 39 (26%) participants in the helmet therapy group and 9 of 40 (23%) participants in the natural course group (odds ratio 1.2, 95% confidence interval 0.4 to 3.3, P=0.74). All parents reported one or more side effects.

Conclusions
Based on the equal effectiveness of helmet therapy and skull deformation following its natural course, high prevalence of side effects, and high costs associated with helmet therapy, we discourage the use of a helmet as a standard treatment for healthy infants with moderate to severe skull deformation.

Salt reduction in England from 2003 to 2011: its relationship to blood pressure, stroke and ischaemic heart disease mortality

April 23, 2014 Comments off

Salt reduction in England from 2003 to 2011: its relationship to blood pressure, stroke and ischaemic heart disease mortality
Source: British Medical Journal

Objectives
To determine the relationship between the reduction in salt intake that occurred in England, and blood pressure (BP), as well as mortality from stroke and ischaemic heart disease (IHD).

Design
Analysis of the data from the Health Survey for England.

Setting and participants
England, 2003 N=9183, 2006 N=8762, 2008 N=8974 and 2011 N=4753, aged ≥16 years.

Outcomes
BP, stroke and IHD mortality.

Results
From 2003 to 2011, there was a decrease in mortality from stroke by 42% (p<0.001) and IHD by 40% (p<0.001). In parallel, there was a fall in BP of 3.0±0.33/1.4±0.20 mm Hg (p<0.001/p<0.001), a decrease of 0.4±0.02 mmol/L (p<0.001) in cholesterol, a reduction in smoking prevalence from 19% to 14% (p<0.001), an increase in fruit and vegetable consumption (0.2±0.05 portion/day, p<0.001) and an increase in body mass index (BMI; 0.5±0.09 kg/m2, p<0.001). Salt intake, as measured by 24 h urinary sodium, decreased by 1.4 g/day (p<0.01). It is likely that all of these factors (with the exception of BMI), along with improvements in the treatments of BP, cholesterol and cardiovascular disease, contributed to the falls in stroke and IHD mortality. In individuals who were not on antihypertensive medication, there was a fall in BP of 2.7±0.34/1.1±0.23 mm Hg (p<0.001/p<0.001) after adjusting for age, sex, ethnic group, education, household income, alcohol consumption, fruit and vegetable intake and BMI. Although salt intake was not measured in these participants, the fact that the average salt intake in a random sample of the population fell by 15% during the same period suggests that the falls in BP would be largely attributable to the reduction in salt intake rather than antihypertensive medications.

Conclusions
The reduction in salt intake is likely to be an important contributor to the falls in BP from 2003 to 2011 in England. As a result, it would have contributed substantially to the decreases in stroke and IHD mortality.

Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial

February 18, 2014 Comments off

Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial (PDF)
Source: British Medical Journal

Objective
To compare breast cancer incidence and mortality up to 25 years in women aged 40-59 who did or did not undergo mammography screening.

Design
Follow-up of randomised screening trial by centre coordinators, the study’s central office, and linkage to cancer registries and vital statistics databases.

Setting 15 screening centres in six Canadian provinces,1980-85 (Nova Scotia, Quebec, Ontario, Manitoba, Alberta, and British Columbia).

Participants 89 835 women, aged 40-59, randomly assigned to mammography (five annual mammography screens) or control (no mammography).

Interventions
Women aged 40-49 in the mammography arm and all women aged 50-59 in both arms received annual physical breast examinations. Women aged 40-49 in the control arm received a single examination followed by usual care in the community.

Main outcome measure
Deaths from breast cancer.

Results
During the five year screening period, 666 invasive breast cancers were diagnosed in the mammography arm (n=44 925 participants) and 524 in the controls (n=44 910), and of these, 180 women in the mammography arm and 171 women in the control arm died of breast cancer during the 25 year follow-up period. The overall hazard ratio for death from breast cancer diagnosed during the screening period associated with mammography was 1.05 (95% confidence interval 0.85 to 1.30). The findings for women aged 40-49 and 50-59 were almost identical. During the entire study period, 3250 women in the mammography arm and 3133 in the control arm had a diagnosis of breast cancer, and 500 and 505, respectively, died of breast cancer. Thus the cumulative mortality from breast cancer was similar between women in the mammography arm and in the control arm (hazard ratio 0.99, 95% confidence interval 0.88 to 1.12). After 15 years of follow-up a residual excess of 106 cancers was observed in the mammography arm, attributable to over-diagnosis.

Conclusion
Annual mammography in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination or usual care when adjuvant therapy for breast cancer is freely available. Overall, 22% (106/484) of screen detected invasive breast cancers were over-diagnosed, representing one over-diagnosed breast cancer for every 424 women who received mammography screening in the trial.

Christmas 2013 Research — Following celebrities’ medical advice: meta-narrative analysis

December 19, 2013 Comments off

Christmas 2013 Research — Following celebrities’ medical advice: meta-narrative analysis
Source: British Medical Journal

Objective
To synthesise what is known about how celebrities influence people’s decisions on health.

Design
Meta-narrative analysis of economics, marketing, psychology, and sociology literatures.

Data sources
Systematic searches of electronic databases: BusinessSource Complete (1886-), Communication & Mass Media Complete (1915-), Humanities Abstracts (1984-), ProQuest Political Science (1985-), PsycINFO (1806-), PubMed (1966-), and Sociology Abstracts (1952-).

Inclusion criteria
Studies discussing mechanisms of celebrities’ influence on people in any context.

Results
Economics literature shows that celebrity endorsements act as signals of credibility that differentiate products or ideas from competitors and can catalyse herd behaviour. Marketing studies show that celebrities transfer their desirable attributes to products and use their success to boost their perceived credibility. Psychology shows that people are classically conditioned to react positively to the advice of celebrities, experience cognitive dissonance if they do not, and are influenced by congruencies with their self conceptions. Sociology helps explain the spread of celebrity medical advice as a contagion that diffuses through social networks and people’s desire to acquire celebrities’ social capital.

Conclusions
The influence of celebrity status is a deeply rooted process that can be harnessed for good or abused for harm. A better understanding of celebrity can empower health professionals to take this phenomenon seriously and use patient encounters to educate the public about sources of health information and their trustworthiness. Public health authorities can use these insights to implement regulations and restrictions on celebrity endorsements and design counter marketing initiatives—perhaps even partnering with celebrities—to discredit bogus medical advice while promoting evidence based practices.

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