Sunday, 25 August 2013

Health myths: Being a bit overweight shortens life

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Health myths: Being a bit overweight shortens life
26 August 2013 by Caroline Williams

Let's be clear – being seriously obese is bad for your health. A body mass index of over 40 increases the risk of type 2 diabetes, heart disease and certain cancers and increases the risk of dying from any cause by up to 29 per cent. This is not a health myth.

But carrying just a few extra pounds, far from being a one-way ticket to an early grave, seems to deter the grim reaper, according to a recent review of nearly a hundred studies involving nearly 3 million people. The review, led by Katherine Flegal of the US Centers for Disease Control in Hyattsville, Maryland, reported earlier this year that being "overweight" – defined as having a body mass index (BMI) of 25 to 29 – seems to have a protective effect, with a 6 per cent ...

Random-effects summary all-cause mortality Hazard Ratios (HRs) for overweight (BMI of 25-<30), obesity (BMI of ≥30), grade 1 obesity (BMI of 30-<35), and grades 2 and 3 obesity (BMI of ≥35) were calculated relative to normal weight (BMI of 18.5-<25). The summary HRs were 0.94 (95% CI, 0.91-0.96) for overweight, 1.18 (95% CI, 1.12-1.25) for obesity (all grades combined), 0.95 (95% CI, 0.88-1.01) for grade 1 obesity, and 1.29 (95% CI, 1.18-1.41) for grades 2 and 3 obesity. These findings persisted when limited to studies with measured weight and height that were considered to be adequately adjusted. The HRs tended to be higher when weight and height were self-reported rather than measured.

Relative to normal weight, both obesity (all grades) and grades 2 and 3 obesity were associated with significantly higher all-cause mortality. Grade 1 obesity overall was not associated with higher mortality, and overweight was associated with significantly lower all-cause mortality. The use of predefined standard BMI groupings can facilitate between-study comparisons.

Full details:

Comment: - lists strengths and weakness.

"... Our study also has limitations. It addresses only all-cause mortality and not morbidity or cause-specific mortality. It addresses only findings related to BMI and not to other aspects of body composition such as visceral fat or fat distribution..."

NHS Direct review

"However, a slight increase in lifespan doesn’t necessarily equate to an increased quality of life. Even being ‘just’ overweight can increase the chance of developing long-term health conditions, which while may not be fatal, can make life a lot less enjoyable."


"The headlines also did not make clear that the increase in life expectancy in people who were overweight or ‘mildly’ obese was modest – they were only 6% less likely to have died by the end of the study period than those of a healthy weight."


This systematic review included a meta-analysis of 97 studies comprising data on 2.88 million people and 270,000 deaths.


This systematic review provides high-quality evidence that obesity grades 2 and 3 are associated with higher death rates from any cause compared to normal weight individuals (around 30% increased risk). However, it also shows that lower grades of obesity (grade 1) do not increase the risk of death relative to normal-weight individuals and, in fact, overweight people had a small but significant reduction in their risk of death in the region of 6%.

The strengths of this review include the large number of studies it included and its standardised approach to searching and extracting data from the literature. Hence, we can be reasonably confident these results reflect reality.

However, a limitation of the study is that it only assessed the risk of dying from any cause (‘all-cause’ mortality), rather than death from specific diseases such as cancer, heart disease or diabetes. The association between weight and risk of death for different disease categories may vary. Disability and living with long-term diseases are also important to people and some conditions such as diabetes may show stronger links with weight at lower thresholds of BMI.

The review also crucially chose BMI as the measure of weight, which has been mistakenly taken by the media to mean an accurate measure of unhealthy ‘fatness’. BMI is a pragmatic choice to assess weight but it does not account for other known disease and death risk factors such as differing fat levels, fat distribution, muscularity, nutritional balance and others. BMI is also an imperfect measure of fatness as it only measures weight and height. Hence, those who are overweight are not all necessarily overweight because they are carrying excess fat. For instance, someone who is very muscular can have a high BMI and therefore be categorised as overweight.

Other measures such as waist circumference offer alternative ways of quickly estimating a person’s body fat levels and whether they are of a healthy weight. In practice, BMI is not the only measure used when establishing risk of disease or death. Doctors will be checking for a host of risk factors like high blood pressure, high cholesterol and high blood glucose levels in addition to BMI and/or waist circumference. Hence, the BMI category is only one of many measures used by a doctor to assess health, and by no means the best.

The finding that overweight individuals were at slightly less risk of dying than their normal-weight counterparts had been reported in research before (this is often referred to as the obesity paradox).

Possible explanations why a bit of extra weight may extend life include:

  • People with more fat reserves to rely on may survive better if they lose weight due to ill health as they get older.
  • Problems associated with being overweight (high blood pressure and diabetes) are picked up and treated earlier in overweight people compared with normal weight, as doctors are more vigilant of risk factors in overweight people. This treatment improves their health overall.

However, it is important to note that these are largely unsubstantiated theories and have not been further explored or proven.

The bottom line is that being obese (all categories combined) increased the chance of dying compared to those with a normal BMI. This was not the case for overweight individuals or the lowest category of obesity (grade 1) on its own.

It is important to consider that individual risk factors for developing disease and death will vary person to person and BMI is only one of many measures used to assess the risk of developing disease in the future.

Even if you choose to ignore the limitations of this research, it would be unwise to interpret its findings as proof that being overweight is ‘healthy’ – rather it may be slightly less unhealthy than perceived.


Change4Life '150 minutes active exercise per week'

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Building activity into your day keeps your heart healthy, reduces your risk of serious illness and strengthens muscles and bones. It can also be a great way of reducing your stress levels and lifting your mood if you’re feeling down.

That means:

  • Adults needs to be active for at least 150 minutes each week
    • Being active means getting your heart rate up, feeling warmer (perhaps even breaking into a light sweat) and making your lungs work harder.

Saturday, 17 August 2013

Oily fish may reduce risk of rheumatoid arthritis - Health News - NHS Choices

reposted from: Oily fish may reduce risk of rheumatoid arthritis - Health News - NHS Choices
crabsallover highlightskey pointscomments / links.

"Eating fish could halve risk of arthritis" is the encouraging news in The Guardian, as a Swedish study found that women who regularly ate high levels of oily fish were less likely to develop rheumatoid arthritis.

This seem to strengthen the Government advice to eat one portion of oily fish and one portion of white fish a week: 'A healthy diet should include at least two portions of fish a week, including one of oily fish.'

Researchers asked women about their diet at two time points a decade apart to assess their intake of long-chain n-3 polyunsaturated fatty acids (omega-3 fatty acids). The researchers then followed up the women six years after their diet was last assessed to see if they had developed rheumatoid arthritis. They found that women whose dietary intake of omega-3 fatty acids consistently exceeded 0.21g per day at both time points had a 52% decreased risk of rheumatoid arthritis compared with women who consistently reported a dietary intake of 0.21g per day or less.

This corresponds to at least one serving of oily fish a week, or four servings a week of lean fish, such as cod. However, the way this study was carried out means that it can't prove that eating fish directly prevented women developing rheumatoid arthritis. Despite this, there are many health benefits from regularly eating oily fish, including a reduced risk of cardiovascular disease.

What were the basic results?

An intake of n-3 PUFAs of more than 0.21g per day (reported on the food frequency questionnaire in 1997) was associated with a 35% decreased risk of developing rheumatoid arthritis compared with a lower intake (adjusted relative risk [RR] 0.65; 95% confidence interval [CI] 0.48-0.90). The researchers calculated that 28% of rheumatoid arthritis cases could be avoided if everyone had an intake of more than 0.21g n-3 PUFAs per day. They also found that higher dietary intakes of n-3 PUFAs further reduced the risk of rheumatoid arthritis until an intake of 0.35g per day was reached. After this level, no additional benefit was seen with a higher intake. When women consistently reported an intake exceeding 0.21g per day (both in 1987 and 1997), this was associated with a 52% (95% CI 29-67%) decreased risk of rheumatoid arthritis compared with women who consistently reported a dietary intake of 0.21g per day or less.

How did the researchers interpret the results?

The researchers conclude that in this study, they have observed a "statistically significant inverse association between intake of dietary long-chain n-3 polyunsaturated fatty acids and rheumatoid arthritis". They go on to suggest that "moderate consumption of fish is sufficient to reduce risk of diseases".


This is a well-designed cohort study that found an association between an increased dietary intake of long-chain n-3 polyunsaturated fatty acids and a reduced risk of rheumatoid arthritis in a cohort of middle-aged and older women in Sweden. This study has many strengths, including: it was prospective, meaning that information was collected as the study was being performed it used a large sample of women taken from the general population diet was assessed at two time points, both long before rheumatoid arthritis was diagnosed But because this is a cohort study, we cannot conclude from its results that dietary long-chain n-3 polyunsaturated fatty acids are directly responsible for the reduction in risk seen. This is because of the confounding factors that could also potentially be responsible for the association seen. Although the researchers adjusted their analyses for the lifestyle factors of smoking and alcohol intake, which are associated with the risk of rheumatoid arthritis, it is possible that people who eat a healthier diet that includes more fatty acids could also have other healthy lifestyle behaviours. This could include having a healthier diet overall (such as a diet with plenty of fruit and vegetables and low in saturated fats) and taking more regular exercise. In addition, this study provides no information about whether dietary intake of long-chain n-3 polyunsaturated fatty acids is associated with a reduced risk of rheumatoid arthritis in men or younger women. Further studies are required to confirm whether long-chain n-3 polyunsaturated fatty acids really do reduce your risk of developing rheumatoid arthritis. However, it is currently recommended that people should aim to eat at least two portions of fish a week, including one portion of oily fish. Babies, children and women who are pregnant, breastfeeding or planning to have children should have no more than two portions of oily fish a week. Eating this amount of fish would provide more than 0.21g of long-chain n-3 polyunsaturated fatty acids, which was the level associated with a reduction in the risk of developing rheumatoid arthritis.

Can excess coffee intake lead to an 'early grave'? - Health News - NHS Choices

Can excess coffee intake lead to an 'early grave'? - Health News - NHS Choices

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New US estimates link obesity to 18% of deaths - Health News - NHS Choices

New US estimates link obesity to 18% of deaths - Health News - NHS Choices

Body Fat % used to calculate obesity

At my new workplace in Poole, Herbalife gave a free "Personal Body Analysis", a 1 minute test for body fat percentage (body fat %). At 168 pounds and 5'7.5" and 57 years I had BMI 25.9 and 29.7% body fat.

Tanita have an explanation and wall charts showing that I am classed as obese (just) based on body fat % basis. The wall chart was based Gallagher et al in 2000 according to Tanita.

Body Fat Ranges for standard adults

The wall chart was based Gallagher et al in 2000.
For males 40-59 years a healthy body fat % is 11-21%.

Tanita's Body Fat Monitors and Body Composition Monitors use Bioelectrical Impedance Analysis (BIA) to help calculate results.