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January 11, 2014 marked the 50th anniversary
of the first Surgeon General’s Report on Smoking and Health. This year the office of Surgeon General has presented half a century's worth
of progress in tobacco prevention and control on their website to commemorate
the 1964 landmark report, by Dr. Luther Terry1. That report was the
first federal government document to link smoking with poor health such as lung
cancer and heart disease.
The
reputation that smoking held during the first half of the 20th century was very
different to how it is viewed today. Smoking became popular in America during
1930s. During this time, smoking was regarded as sophisticated and glamorous.
Due to its newfound popularity, research on smoking during this era often
failed to find clear evidence of serious pathology.
In 1947, Richard Doll and
A. Bradford Hill of the British Medical Research Council created a statistical
technique to evaluate the dangers of smoking. In 1950 they published an article
in the BMJ2 documenting the association
between rising rates of lung cancer and increasing numbers of smokers.
In 1950, Wynder EL, a
medical student, and Graham EA, published a landmark article in JAMA3
comparing the incidence of lung cancer in their nonsmoking and smoking
patients at Barnes Hospital in St. Louis. They concluded “cigarette smoking, over a long period, is at
least one important factor in the striking increase in bronchogenic cancer.”
Tobacco
use remains the single largest preventable cause of death and disease in the
United States according to the Centers forDisease Control and Prevention (CDC).
Cigarette smoking kills more than 480,000 Americans each year, with more than
41,000 of these deaths due to exposure to secondhand smoke. In addition,
smoking-related illness in the United States costs more than $289 billion a
year, including at least $133 billion in direct medical care for adults and
$156 billion in lost productivity.
The CDC states that smoking harms nearly every organ of the body. In
fact, smoking is the cause for one in five deaths in the United States. Smoking
can cause cancer in almost every organ (bladder, blood-acute myeloid leukemia,
cervix, colon and rectum, esophagus, kidney and ureter, larynx, liver,
oropharynx-includes parts of the throat, tongue, soft palate, and the tonsils,
pancreas, stomach, trachea, bronchus, and lung).
•
Smoking causes about 90% of all lung cancer
deaths in men and women and 80% of chronic obstructive pulmonary disease
(COPD).
•
Smoking is estimated to increase the risk for
coronary heart disease and stroke by 2 to 4 times and for lung cancer by 25
times.
Two
recent studies present risks from smoking and its prevalence in the different
countries across the globe.
Jacobs et al
research that was published in the Annals ofEpidemiology analyzed data on smoking rates
from the National Health Interview Survey, as well as data on the risks of
smoking from epidemiologic studies, to estimate the proportion of U.S. cancer
deaths caused by smoking— what the researchers called the population attributable fraction
(PAF).
The
researchers looked at deaths from the 12 cancers formally linked to smoking by
the U.S. surgeon general and they observed that the PAF was 28.7 percent.
However, after factoring in cancer deaths than may have been caused by smoking,
the PAF was 31.7 percent. These estimates don’t factor in other potential cancer deaths caused by secondhand
smoke or other kinds of smoking such as cigars, pipes or smokeless tobacco.
While there
has been a decline in smoking prevalence, the current and previous PAF
estimates may remain similar due to the addition of new cancers that may be
caused by smoking, higher rates of lung cancer deaths among female smokers, and
a greater focus on reducing deaths from cancer caused by factors other than smoking.
However, the authors noted that efforts to reduce
smoking haven’t
been futile. According to the CDC, more than 40 percent of Americans smoked in
the 1960s, but today, only 18 percent of Americans smoke.
The group by Ng et al reported In JAMA the prevalence and cigarette
consumption in 187 Countries between the years 1980-2012.
The
researchers identified nationally representative sources that measured tobacco
use (n = 2102 country-years of data) and
synthesized age-sex-country-year observations (n = 38 315) using spatial-temporal
Gaussian process regression to model prevalence estimates by age, sex, country,
and year.
Globally
modeled age-standardized prevalence of daily tobacco smoking in the population
older than 15 years decreased from 41% in 1980 to 31% in 2012 for men and from
10% to 6% for women. Despite the decline in prevalence, the number of daily
smokers increased from 721 million in 1980 to 967 million in 2012. The populous China is home to
more than 300 million smokers and 43% of the world’s cigarette production. The World Health
Organization estimates that smoking kills more than one million of the Chinese
population each year and the cost from death and complications related to
smoking would have cost China $500 billion in the decade ending in 2015. Modeled
prevalence rates exhibited substantial variation across age, sex, and
countries, with rates below 5% for women in some African countries to 57% for
men in Indonesia. The following are some
examples of prevalence of smoking in males, females and both sexes in few
countries with Greece having the most overall smokers and the United States the
fewer while Indonesia has the most male smokers and the fewer female smokers.
Countries Males Females Both sexes
Greece 41% 35% 38%
Indonesia 57% 4% 37%
US 17% 14% 16%
The authors
concluded that since 1980, large reductions in the estimated prevalence of
daily smoking were observed in both men and women, but because of population
growth, the number of smokers increased significantly.
Given the
importance of tobacco as a risk to health, monitoring the distribution and
intensity of tobacco use is critical for identifying priority areas for action
and for evaluating progress. Recent
studies in multi-country survey programs have substantially expanded the
primary data available for monitoring. The most recent cross-sectional
estimates of smoking prevalence were for 2011 and the publication of The Tobacco Atlas has greatly
facilitated the development of policies based on these data.
Since the release
of the Surgeon General report on the adverse effects of smoking, a wide range
of interventions became available, including increasing prices and bans on
advertising, promotion, sales to minors, and smoking in public places. The
adoption of the Framework Convention on Tobacco Control (FCTC) in 2003 and its
subsequent ratification by 177 countries reflects growing global efforts to
control tobacco. Despite such efforts, tobacco continues to adversely influence
global health patterns, leading to 5.7 million deaths, 6.9% of years of life
lost, and 5.5% of disability-adjusted life-years (DALYs) in 2010 requiring that
efforts towards further decrease and/or elimination of smoking across the
planet should continue.
References
1. Terry, Luther et al. Smoking and Health:
Report of the Advisory Committee to the Surgeon General of the United States.
U-23 Department of Health, Education, and Welfare. Public Health Service
Publication No. 1103. 1964 May
3. Doll R, Hill AB. Smoking and carcinoma of the lung:
preliminary report. British Medical
Journal 1950:2 739-48
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Thursday, January 1, 2015
Cigarette smoking remains a leading cause of Death
Tuesday, December 2, 2014
Obesity’s costs; Is there a solution?
The McKinsey Global Institute reported the
worldwide cost of obesity to be 2 trillion dollars annually, or 2.8 percent of
global GDP. Costs from it
are approximately the same as from smoking or armed conflicts making it one of
the three top global burdens. Obesity
is responsible for about 5 percent of all deaths every year worldwide.
2.1 billion people - about 30% of the world's
population - were overweight or obese creating a "steep economic
toll", and the proportion could rise to almost half of the world's
population by 2030. The
financial costs of obesity therefore due to illnesses it is causing.
Although the debate on this issue has become
polarized and sometimes deeply antagonistic, obesity is a complex, systemic
issue. The McKinsey Global Institute report proposes that,
• Existing evidence indicates that no
single intervention is likely to have a significant impact, thus capturing the
full potential requires engagement from as many sectors as possible.
• Education and personal responsibility
are critical elements of any program aiming to reduce obesity. They include
reducing default portion sizes, changing marketing practices, and restructuring
urban and education environments to facilitate physical activities.
The advice usually given to obese individuals
who want to loose weight focuses on consuming fewer calories and exercising
more. The benefits of Mediterranean diet and of such foods as vegetables,
fruits, nuts, fiber and fish, are often also touted. However, mounting evidence reveals
that the most common eating pattern in modern societies of three meals daily,
plus snacks, is abnormal from the perspective of human evolution, a group of
researchers wrote in an article published in the journal Proceedings of the National Academy of Sciences suggesting
that intermittent fasting could have benefits.
Ancient hunter-gatherers often ate only
intermittently, and only when they had a successful hunting. This suggests that
the ability to function at a high level both physically and mentally during
extended periods without food may have been crucial in human evolution, and
that the human body may have adapted to perform at its best with intermittent
fasting. Such intermittent
fasting could consist of eating 500 calories or less either two days each week,
or every other day, or not eating breakfast and lunch several days each week,
the researchers said.
Sunday, November 2, 2014
Low Carbohydrate & Low Fat Diets the Same for Weight Loss
Many claims in lay media and
scientific literature have been made regarding the superiority of a certain diet
for inducing weight loss. Two recent studies
one published in the Journal of the American
Medical Association and the second in Annals
of Internal Medicine found that using either a low-carbohydrate or low-fat diet had the same end result. The best diet
is that which works best for the dieter.
Johnston et al report in JAMA finding
from their search of 6 electronic databases based on which they estimated the
relative effectiveness of diets to affect weight and body mass index from
baseline. Weight loss and body mass
index was determined at 6- and 12-month follow-up.
Among 59 eligible articles reporting
48 unique randomized trials that included 7286 individuals, the largest weight
loss was associated with low-carbohydrate diets 8.73 kg at 6-month follow-up
and 7.25 kg at 12-month follow-up and low-fat diets 7.99 kg at 6-month
follow-up and 7.27 kg at 12-month follow-up. Weight loss differences between
individual diets were minimal. For example, the Atkins diet resulted in a 1.71
kg greater weight loss than the Zone diet at 6-month follow-up.
They concluded significant weight
loss was observed with both low-carbohydrate or low-fat diet. Weight loss
differences between individual named diets were small.
In the
study by Bazzano et al published by the Annals of Internal Medicine, the effects
of a low-carbohydrate diet compared with a low-fat diet of on body weight and
cardiovascular risk factors was determined.
148 men and women without
clinical cardiovascular disease and diabetes were placed on a low-carbohydrate
(<40 g/d) or low-fat (<30% of daily energy intake from total fat [<7%
saturated fat]) diet.
Data on weight, cardiovascular
risk factors, and dietary composition were collected at 0, 3, 6, and 12 months.
Sixty participants (82%) in the
low-fat group and 59 (79%) in the low-carbohydrate group completed the
intervention. At 12 months, participants on the low-carbohydrate diet had
greater decreases in weight (mean difference in change, −3.5 kg), fat mass
(mean difference in change, −1.5%), ratio of total–high-density lipoprotein
(HDL) cholesterol (mean difference in change, −0.44), and triglyceride level
(mean difference in change, −0.16 mmol/L) and greater increases in HDL
cholesterol level (mean difference in change, 0.18 mmol/L) than those on the
low-fat diet.
They concluded low-carbohydrate
diet was more effective for weight loss and cardiovascular risk factor
reduction than the low-fat diet.
Based on these studies both
low-carb and low-fat diets induced weight
loss but there was not a sizable differences between the two. Finally, the
branding of the diet did not have an impact on weight loss.
Thursday, October 2, 2014
Cancers linked to Obesity
Obesity is a
major contributor to the development of cancer.
According to the National Cancer Institute obesity is associated with increased risks for cancer of the
esophagus, pancreas, colon and rectum, breast (after menopause), endometrium,
kidney, thyroid, and gallbladder.
NHANES 2007-2008 survey found 68 percent of the U.S.
adults age 20 years and older are overweight or obese and 17 percent of
children and teens ages 2 to 19, are obese.
According to NCI Surveillance,
Epidemiology, and End Results (SEER) data, it is estimated that in 2007 in the
United States, about 34,000 new cases of cancer in men (4 percent) and 50,500
in women (7 percent) were due to obesity.
In 2003, Calle et
al published in NEJM the results of a
study of more than 900,000 healthy adults that were followed for 16 years. The
study authors concluded that excess fat could account for 14% of all deaths
from cancer in men and 20% of those in women.
A recent study of
92,834 British women enrolled in a database for cancer screening, Fourkala et al reported in an article published in BMJ Open that women who go up a skirt size every decade between their
20s and their 60s are at increased risk of postmenopausal breast cancer. They also found that “an increase of one size
every 10 years led to a 33 percent rise in the risk of postmenopausal breast
cancer, while an increase of two sizes per decade led to a 77 percent rise in
risk.
Bhaskaran et al study of 5.2 million adults that was published in Lancet found that 166 955 individuals developed cancer and that body-mass
index (BMI) was associated with 17 of 22 cancers. Although the effects varied substantially by
site, increase in BMI was
roughly linearly associated with cancers of the uterus, gallbladder, kidney,
cervix, and leukemia. BMI increase was
positively associated with liver, colon, ovarian, and postmenopausal breast
cancers overall.
They estimated inverse associations with prostate and premenopausal breast
cancer risk, both overall and in non-smokers. By contrast, for lung and oral
cavity cancer, they observed no association in non-smokers. Assuming causality, 41% of uterine and 10% or
more of gallbladder, kidney, liver, and colon cancers could be attributable to
excess weight. They conclude that extra weight could contribute to
more than 12,000 cases of cancer in the UK population every year.
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