Roundup: Risk Factors Involving Lifestyle Choices Linked to 40% of Cancer Cases; and More News

American Cancer Society: Modifiable Risk Factors Linked to 40% of Cancer Cases, Nearly Half of all Deaths

Four in 10 cancer cases (40 percent) -- and about one-half of all U.S. cancer deaths in adults aged 30 or older -- could be attributed to “modifiable risk factors, including cigarette smoking, excess body weight, alcohol consumption, physical inactivity, diet, and infections,” according to findings by researchers at the American Cancer Society published in the journal CA: A Cancer Journal for Clinicians.

Cigarette smoking was by far the leading risk factor, contributing to nearly 20 percent of all cancer cases and 30 percent of all cancer deaths.

“Despite considerable declines in smoking prevalence during the past few decades, the number of lung cancer deaths attributable to cigarette smoking in the United States is alarming,” said Farhad Islami, M.D., senior scientific director, cancer disparity research at the American Cancer Society and lead author of the report, in a statement. “This finding underscores the importance of implementing comprehensive tobacco control policies in each state to promote smoking cessation, as well as heightened efforts to increase screening for early detection of lung cancer, when treatment could be more effective,”

Researchers relied on nationally representative data on cancer incidence and mortality, as well as risk factor prevalence, to estimate the proportion and number of cancer cases and deaths attributable to potentially modifiable risk factors overall (excluding non-melanoma skin cancers) and for 30 cancer types.

These risk factors included cigarette smoking (current and former smoking); secondhand smoke; excess body weight; alcohol consumption; consumption of red and processed meat; low consumption of fruits and vegetables, dietary fiber, and dietary calcium; physical inactivity; and ultraviolet (UV) radiation;

Infections were also included as risk factors. Those included Epstein-Barr virus (EBV), Helicobacter pylori, hepatitis B virus (HBV), hepatitis C virus (HCV), human herpes virus-8 (HHV-8; also called Kaposi sarcoma herpesvirus), human immunodeficiency virus (HIV), and human papillomavirus (HPV).

The results: Cigarette smoking had the largest population attributable fraction (PAF) or proportion of cancer cases attributable to risk factors in the population (344,070 cases; 19.3 percent of all cases), contributing to 56.0 percent of all potentially preventable cancers in men (206,550 of 368,600) and 39.9 percent in women (137,520 of 344,740).

Excess body weight had the second largest PAF (7.6 percent), followed by alcohol consumption (5.4 percent), UV radiation exposure (4.6 percent), and physical inactivity (3.1 percent).

By cancer type, the proportion of cases caused by potentially modifiable risk factors ranged from 100 percent for cervical cancer and Kaposi sarcoma to 4.9 percent for ovarian cancer, and exceeded 50 percent for 19 of 30 evaluated cancer types.

In addition to cervical cancer and Kaposi sarcoma, more than 80 percent of all melanomas of the skin (92.2 percent) and cancers of the anus (94.2 percent), larynx (89.9 percent), lung and bronchus (88.2 percent), pharynx (87.4 percent), trachea (85.6 percent), esophagus (85.4 percent), and oral cavity (83.7 percent) were attributable to evaluated risk factors.

Lung cancer had the largest number of cases attributable to evaluated risk factors in both men (104,410 cases) and women (97,250), followed by skin melanoma (50,570), colorectal cancer (44,310), and urinary bladder cancer (32,000) in men and by breast (83,840), corpus uteri (35,790), and colorectal (34,130) cancer in women.

“Interventions to help maintain healthy body weight and diet can also substantially reduce the number of cancer cases and deaths in the country, especially given the increasing incidence of several cancer types associated with excess body weight, particularly in younger individuals,” Dr. Islami added in his statement.

Nearly 10% of Women Infected During Pregnancy Get Long COVID – Higher Average Than Overall Population

Nearly one in 10, or 10 percent, of women who get COVID while pregnant will go on to develop lingering or persistent symptoms, a condition known as “long COVID,” according to a new study published in Obstetrics & Gynecology.

The research is the first to indicate that long covid may be more prevalent among people infected while pregnant than in the population overall. As many as 7 percent of U.S. adults report having symptoms associated with long COVID, states a 2022 report from the U.S. Centers for Disease Control and Prevention (CDC). Some surveys indicate that the incidence of long COVID in the general population could be even higher.

Prior research had shown that COVID puts pregnant women at risk of serious complications. A COVID infection during pregnancy is more likely to lead to hospitalization or death, compared to an infection outside of pregnancy, states a news release on the new study. COVID also increases the risk of pregnancy-related complications such as preterm birth or stillbirth. But until this new report, the risk to pregnant people of developing long COVID was relatively unknown.

“It was surprising to me that the prevalence was that high,” states Torri Metz, M.D., vice chair of research of obstetrics and gynecology at University of Utah Health, who co-led the nationwide study, in a statement. “This is something that does continue to affect otherwise reasonably healthy and young populations.”

The researchers enrolled more than 1,500 women nationwide who had been sick with COVID for the first time while pregnant. They reviewed self-reported long COVID symptoms at least six months after infection. The study was funded as part of the National Institutes of Health (NIH) RECOVER project, a nationwide collaboration to understand and treat long COVID.

The researchers found that nearly 10 percent of women who contracted COVID during pregnancy went on to experience long-term symptoms. Some of the most common long COVID symptoms participants experienced were fatigue, gastrointestinal issues, and feeling drained or exhausted by routine activities.

"This is a critical study as pregnancy and the post-partum period are one of the most vulnerable times in an individual's life," said David Goff, M.D., Ph.D., division director for the Division of Cardiovascular Sciences at the NIH’s National Heart, Lung, and Blood Institute. "By better understanding how individual characteristics interact with SARS-CoV-2 (COVID-19) infection during pregnancy and lead to an increased risk of long COVID, this study yields important insights to potentially develop targeted interventions for this population."

Cycling or Walking to Work Safely Linked to Lower Risk of Early Death, Long-Term Study Finds

Commuters who can cycle or walk to and from work safely lower their risk of early death from any cause by as much as 47 percent, compared to those who don’t actively commute, according to a large long-term study published in the journal BMJ Public Health.

While researchers in Scotland saw health benefits as a result of both types of active commuting, the strongest health benefits were seen for cyclists, the findings show. Active travel, and not relying automobiles or mass transit options, is considered to be one of the “most practical and sustainable ways to increase daily physical activity,” states a news release on the study.

Researchers drew on nationally representative data from the Scottish Longitudinal Study (SLS), which is based on 5 percent of the Scottish population derived from Census returns in 1991, 2001, and 2011. 

The researchers focused on commuters 16 to 74 years of age in 2001 who travelled to work or study in the U.K. The final analysis was based on 82,297 people. Specifically, commuting bicycle was associated with a 47 percent lower risk of death, a 10 percent lower risk of any hospital admission, and a 24 percent lower risk of hospital admission for cardiovascular disease. 

However, cycling commuters “were twice as likely as ‘inactive’ commuters to be admitted to hospital after a road traffic collision,” states the news release.

Researchers: “This study has wider global relevance to efforts to reduce carbon emissions and to shift to more active and sustainable travel modes.” But they also issued this caution: “Our finding that cyclist commuters have twice the risk of being a road traffic casualty compared with non-active commuters reinforces the need for safer cycling infrastructure.”