Cancer may become the leading cause of death by 2020

The Centers for Disease Control (CDC) looked at data for the five leading causes of death (heart disease, cancer, stroke, chronic lower respiratory diseases, and accidents) which together account for 63 percent of all deaths in the United States,. 

They used mortality data, population estimates and projections to estimate and predict heart disease and cancer deaths from 1969 through 2020.

The report indicates that fewer people died prematurely from cancer, stroke and heart disease between 2010 and 2014.

They predicted that from 1969 through 2020, the number of heart disease deaths would decrease 21.3% among men and 13.4% among women while the number of cancer deaths would increase 91.1% among men and 101.1% among women. They suggest that cancer would become the leading cause of death around 2016.

In 2014, more than 614,000 Americans died of heart disease and approximately 592,000 died of cancer that year.  However, in 2016, almost 601,000 Americans may die as a result of cancer, while more than 597,000 may die from heart disease.  Thus cancer could surpass heart disease as the leading cause of death among Americans this year, according to the report.

The authors conclude that the risk of death declined more steeply for heart disease than cancer over the past 4 decades. If current trends continue, cancer will become the leading cause of death by 2020.

Obesity linked to premature death

It is well known that being overweight can lead to health complications including diabetes, heart disease, stroke and cancer.

A recent study published in Lancet reports on a meta-analysis of 239 prospective studies published from 1970 to last year (median follow-up 13·7 years).  Of those 3 951 455 people in 189 studies were never-smokers without chronic diseases at recruitment who survived 5 years, of whom 385 879 died.   The investigators extracted their information from 10 625 411 participants in Asia, Australia and New Zealand, Europe, and North America.

They compared the risk of death to people's body mass index, or BMI, a measure of body fat that is calculated using height and weight.  They defined a BMI from 18.5 to 25 as normal, 25-30 as overweight, 30-35 as moderately obese and over 40 as severely obese.

In the study, the risk of dying before the age of 70 was 19 percent for men and 11 percent for women of normal weight.

But that risk jumped to 30 percent and 15 percent, respectively, for obese men and women.  The investigators found that overweight people die one year earlier than expected and that moderately obese people die up to three years prematurely.

The World Health Organization estimates that 1.3 billion adults worldwide are overweight, and 600 million more are obese. The associations of both overweight and obesity with higher all-cause mortality were broadly consistent in all four continents. As common diseases such as heart disease, stroke, diabetes and cancer have been strongly associated to obesity, strategies to combat it are needed all around the globe.

Decades long decline in Dementia

A study by Satizabal et al published in the NEJM found that dementia rates fell steadily over the past three decades, likely due to declining rates of heart disease.

The study analyzed data collected since 1975 from the Framingham Heart Study and included 5205 persons 60 years of age or older.  The authors compared interactions between epoch and age, sex, apolipoprotein E ε4 status, educational level, as well as the effects of vascular risk factors such as cardiovascular disease on the prevalence of dementia.

The 5-year age-and sex-adjusted cumulative hazard rates for dementia were 3.6 per 100 persons during the first epoch (late 1970s and early 1980s), 2.8 per 100 persons during the second epoch (late 1980s and early 1990s), 2.2 per 100 persons during the third epoch (late 1990s and early 2000s), and 2.0 per 100 persons during the fourth epoch (late 2000s and early 2010s). Relative to the incidence during the first epoch, the incidence declined by 22%, 38%, and 44% during the second, third, and fourth epochs, respectively. This risk reduction was observed only among persons who had at least a high school diploma. The prevalence of most vascular risk factors (except obesity and diabetes) and the risk of dementia associated with stroke, atrial fibrillation, or heart failure have decreased over time, but none of these trends completely explain the decrease in the incidence of the disease.

The authors concluded that the incidence of dementia has declined over the course of three decades.

N Engl J Med 2016; 374:523-532

Obesity

A study by Ng et al reports on the prevalence of obesity in countries around the world.  Their research that was supported by Bill and Melinda Gates Foundation and published in Lancet, reviewed more than 1,700 studies covering 188 countries from 1980 to 2013.

The study found more than 2.1 billion individuals worldwide are overweight or obese, up from 857 million in 1980.  Also, obesity was estimated to have caused 3·4 million deaths, 3·9% of years of life lost, and 3·8% of disability-adjusted life-years worldwide in 2010.

They based their analysis on body-mass index (BMI) a measure of weight and height.  Individuals with a BMI of 30 or more are considered obese, while those a BMI of 25 to 29.9 are considered overweight, according to the U.S. National Institutes of Health.

Worldwide, the proportion of adults with a BMI of 25 or greater increased between 1980 and 2013 from 28·8% to 36·9% in men, and from 29·8% to 38·0% in women. In the US, 87 million individuals or 27.2% were obese according to study conducted in 2013 (Gallup). The prevalence of obesity has increased in children and adolescents worldwide.  In 2013, 23·8% of boys and 22·6% of girls were overweight or obese in developed countries, while in developing countries 12·9% of the boys and 13·4% of the girls were overweight or obese. One of the “most troubling” findings of the study is that the percentage of overweight or obese children and teenagers has increased by nearly 50 percent since 1980.   In the US alone, nearly 30 percent of the children and teens are either obese or overweight, up from 19 percent in 1980.

More than half of the world’s 671 million obese people live in the U.S., China, India, Russia, Brazil, Mexico, Egypt, Germany, Pakistan and Indonesia.  During the more than three decades studied, the largest increase in obesity rates were in Egypt, Saudi Arabia, Oman, Honduras and Bahrain for women and New Zealand, Bahrain, Kuwait, Saudi Arabia and the U.S. for men.  In adults, the estimated prevalence of obesity exceeded 50% in men in Tonga and in women in Kuwait, Kiribati, Federated States of Micronesia, Libya, Qatar, Tonga, and Samoa.  Since 2006, the increase in adult obesity in developed countries has slowed down.  

Because obesity can raise the risk of diabetes, osteoarthritis, heart disease and cancer, among other health-threatening conditions, strategies to correct it such increase physical activity, decrease of total caloric intake and selectivity the foods eaten are needed as obesity represents a major global health challenge.

Addendum:  A study based on review of the health records of 65,000 that was published in JAMAPediatrics (9/29/14) suggests infants and young children with repeated exposure to broad-spectrum antibiotics at ages 0-23 months are associated with childhood obesity.