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Take a look at a selection of our recent media coverage:
1st July 2022
Patient who have undergone bariatric surgery have a significantly lower risk of developing an obesity-related cancer as well as cancer-related mortality. This was the conclusion of a cohort study by a team of US researchers.
Individuals with a body mass index (BMI) above 25 are considered to be overweight but when the BMI exceeds 30, these individuals are deemed to be obese. Data from the World Health Organisation suggest that in 2016, 1.9 billion adults across the world were classed as overweight and 650 million obese. Although obesity increases the risk of cardiovascular disease, obesity has also been found to be associated with greater overall mortality in patients with cancer.
Whilst dieting helps many people to lose weight, one of the most effective weight loss strategies is surgery and in one follow-up study after a Roux-en-Y gastric bypass, the mean weight loss change from baseline was 35 kg at 12 years. Given the elevated risk of certain cancers in those who are obese, could weight loss reduce the risk of subsequently developing an obesity-related cancer? Unfortunately, the evidence base supporting this premise is limited apart from one study in patients who underwent bariatric surgery and which found that after a mean follow-up of 12.5 years, total cancer incidence was significantly lower in the surgical group compared to controls. Nevertheless, a limitation of the study was the absence of a matched control group, particularly in relation to possible cancer risk factors such as smoking history.
Consequently, there remains some uncertainty over whether weight loss can reduce the risk of cancer and this was the basis for the current study. The US team undertook the Surgical Procedures and Long-term Effectiveness in Neoplastic Disease Incidence and Death (SPLENDID) trial, which was a retrospective, observational, matched, cohort study in adults with obesity who either underwent bariatric surgery or who received usual care (i.e., no surgery). Participants were included if they had a BMI of between 35 and 80 and underwent either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). The primary endpoint of the study was the first occurrence of 1 of 13 types of obesity-associated cancers including oesophageal adenocarcinoma, renal cell carcinoma, colon, rectum, liver and pancreatic cancer. As a secondary endpoint, the team considered the incidence of all types of cancer and cancer-related mortality.
Bariatric surgery and cancer development
A total of 30,318 patients with a median age of 46 years (77% female) including 5,053 who underwent bariatric surgery, (RYGB 66%) were included in the analysis. After 10 years, participants in the bariatric surgery group had lost 27.5 kg compared to 2.7 kg in the control group (p <0.001).
During the period of follow-up, 96 patients in the bariatric surgery group and 780 in the control group developed one of the obesity-related cancers, giving an incidence rate of 3 vs 4.6 events (surgery vs control) per 1000 person-years.
The cumulative incidence of the primary endpoint at 10 years was 2.9% in the surgery group and 4.9% in the non-surgical (control group) and which was statistically significant (hazard ratio, HR = 0.68, 95% CI 0.53 – 0.87, p = 0.02). In addition, the cumulative incidence of cancer-related mortality at 10 years was 0.8% in the surgical group compared to 1.4% in the control group and which again, as statistically significant (HR = 0.52, 95% CI 0.31 – 0.88, p = 0.01).
Based on these findings, the authors concluded that bariatric surgery is associated with a significantly lower incidence of obesity-associated cancer and cancer-related mortality.
Aminian A et al. Association of Bariatric Surgery With Cancer Risk and Mortality in Adults With Obesity JAMA 2022
6th June 2022
Drinking coffee sweetened with sugar provides broadly similar mortality benefits to consumption of unsweetened coffee although benefits from drinking coffee sweetened with artificial agents are much less consistent. This was the finding of a prospective cohort study by a team of researchers based at the Department of Epidemiology, School of Public Health, Southern Medical University, Guangdong, China.
A 2019 meta-analysis concluded that moderate coffee consumption, for example, 2 to 4 cups every day, was associated with reduced all-cause and cause-specific mortality in comparison to those who did not consume the beverage. In fact, consumption of 8 or more cups of coffee per day, even among those with slower or faster caffeine metabolism, has been shown to be inversely associated with mortality. Nevertheless, what has not been explored in the literature is the extent to which sweetened coffee retains these health benefits, given the potential adverse health effects of sweetened beverages.
For the present study, the researchers turned to data held in the UK Biobank to determine the association between consumption of coffee sweetened with either sugar or artificial agents and overall and specific cause mortality. A further objective was to explore whether sweetening affected any mortality benefits depending on how the coffee was prepared, e.g., instant, ground, or decaffeinated. Participants in the UK Biobank completed dietary recall data using a web-based questionnaire from which the researchers collected information on whether sugar or artificial sweeteners were used in coffee. The level of coffee consumption was categorised as 0 – 1.5 cups/day, > 1.5 – 2.5 cups/day, > 2.5 – 3.5 cups/day and > 4.5 cups/day and the type of coffee drank was classed as instant, ground or decaffeinated. Regression analysis was used to estimate the hazard ratios for coffee consumption and mortality, adjusted for several factors such as age, gender, co-morbidities etc.
Coffee sweetened with sugar/artificial agents and mortality outcomes
A total of 171,616 individuals with a mean age of 55.6 years (44.6% male) were included in the final analysis and followed for a median of 7 years. Among this cohort, 24.2% were non-coffee drinkers, 55.4% drank unsweetened coffee with the remainder adding either sugar (14.3%) or artificial sweeteners (6.1%). Those who sweetened their coffee added an average of 1.1 teaspoons of sugar and 1.4 teaspoons of a sweetener.
During the follow-up period there were 3177 deaths, 1725 from cancer and 628 from CVD. Compared with those who did not drink coffee, after adjustment, the risk of death associated with drinking > 3.5 to 4.5 cups of unsweetened coffee/day was 29% lower (hazard ratio, HR = 0.71, 95% CI 0.60 – 0.84). For those drinking a similar amount of coffee sweetened with sugar, there was a similar reduced risk of death (HR = 0.79, 95% CI 0.60 – 1.06). For the same level of consumption, drinking coffee sweetened with an artificial agent had a significant all-cause mortality benefit (HR = 0.65, 95% CI 0.45 – 0.92).
When considering how the coffee was prepared, there were significant mortality benefits associated with drinking > 3.5 to 4.5 cups/day of unsweetened coffee. In contrast, the mortality benefits for a similar level of consumption of sugar-sweetened coffee were slightly less and non-significant for all three methods of preparation. Among those using artificial sweeteners, benefits were derived from instant (HR = 0.66, 95% CI 0.46 – 0.96) and ground coffee (HR = 0.51, 95% CI 0.27 – 0.95) but not decaffeinated (HR = 0.52, 95% CI 0.23 – 1.17).
The authors concluded that taking the data as a whole, it seemed that consumption of either unsweetened or sugar-sweetened coffee provided broadly similar mortality benefits. In contrast, the effect of sweetening coffee with artificial agents was less consistent, possibly due to the smaller number of people in this group.
Liu D et al. Association of Sugar-Sweetened, Artificially Sweetened, and Unsweetened Coffee Consumption With All-Cause and Cause-Specific Mortality. A Large Prospective Cohort Study Ann Intern Med 2022
25th January 2022
A higher olive oil intake has been linked to a lower all-cause and cardiovascular mortality compared to those who either never or rarely consume it. This was the finding of a study by researchers from the Department of Nutrition, Harvard T.H. Chan School of Public Health, Massachusetts, USA.
Olive oil (OO) consumption has been associated with a myriad of health benefits due to the presence of monounsaturated fatty acids which possess anti-inflammatory and anti-oxidant properties. Moreover, evidence from epidemiological studies show that greater olive oil intake and in-particular, extra virgin olive oil, is associated with a 39% lower risk of cardiovascular disease. Nevertheless, there is a paucity of data on the relationship between total olive oil intake on both all-cause and cause-specific mortality.
For the present study, the Harvard team used data from two ongoing prospective US cohort studies, the Nurses Health Study (NHS) which began in 1976 and the Health professionals Follow-up study (HPFS) which started in 1986. In both studies, participants are sent questionnaires, every two years to assess lifestyle factors and health status and for the present analysis, team used the baseline level of OO intake which was first captured in 1990. For the purposes of the analysis, one tablespoon was considered to be equivalent to 13.5 g of OO. Consumption of olive oil was then categorised by frequency as never or less than once/month (the reference point), > 0 < 1 teaspoon, > 1 to < 2 teaspoons and greater than half a tablespoon (equivalent to > 7 gm/day.
The researchers identified both the total number of deaths during the period of follow-up and the cause from medical records. Multivariable regression analysis was used to estimate the risk of total and cause-specific mortality and models were adjusted for a number of covariates such as age, gender, smoking status, body mass index etc.
During a 28 year follow-up period, there were 36,856 deaths and the mean OO consumption increased from 1.6g/day in 1990 to 4g/day in 2010.
Among those with the highest intake of OO, compared to the reference category, there was 19% reduced risk of total mortality (Hazard ratio, HR = 0.81, 95% CI 0.78 – 0.87) and cardiovascular mortality (HR = 0.81, 95% CI 0.75 – 0.89). In addition, the researchers found that increased OO intake reduced the risk of cancer and neurodegenerative mortality by 29% and 18% respectively.
In a further analysis, the Harvard team considered the mortality benefits of substituting other sources of fat with olive oil. For example, they calculated that replacing 10 g/day of margarine with an equivalent amount of OO was associated with a 13% lower risk of mortality and similar reductions were seen for butter, mayonnaise and dairy fat. They also observed that these reduced risk were also consistent for other causes of death.
They concluded that greater consumption of olive oil lead to reductions in all-cause and cause-specific mortalities and such reductions in risk could also be achieved when other types of fat were replaced with olive oil.
Guash-Ferre M et al. Consumption of Olive Oil and Risk of Total and Cause-Specific Mortality Among U.S. Adults J Am Coll Cardiol 2022
25th October 2021
Physical inactivity could be the cause of 46,356 cancer cases across the US based on an analysis by researchers from the Department of Surveillance and Health Equity Science, Atlanta, US, on behalf of the American Cancer Society. The importance of undertaking physical activity as a means of reducing the risk of cancer, was highlighted in a 2019 systematic review which found strong evidence for an association between the highest versus lowest physical activity levels and reduced risks of bladder, breast, colon, endometrial, oesophageal adenocarcinoma, renal and gastric cancers. The review also identified how greater amounts of physical activity reduced cancer-specific mortality in those with breast, colorectal, or prostate cancer, with relative risk reductions of between 40 and 50 percent.
But how the risk of cancer due to physical inactivity vary across different states in the US was the question posed in the study by the American Cancer Society. The researchers estimated the proportion of cancer cases attributable to physical inactivity overall and for seven types of cancer (oesophagus, stomach, colon, breast in women, corpus uteri, kidney and bladder). The researchers drew on data from the Behavioural Risk Factor Surveillance System (BRFSS), which collects state-level estimates of various health-related behaviours including information on physical activity. The information on physical activity was drawn from surveys conducted between 2003 and 2006 across a wide age range and the number of incident cancer cases in 2013 – 2016, were obtained from the US Cancer Statistics database, to allow for a lag time between exposure prevalence and the occurrence of cancer.
The levels of physical activity were categorised in terms of metabolic equivalent task (MET) hours/week. A MET is the amount of energy an average adult expends sitting at rest. With the US physical activity guidelines recommending that adults engage in 2.5 to 5 hours/week of moderate intensity activity, this equates to at least 7.5 – 15 MET hours/week. For the purposes of their analysis, the researchers defined optimal physical activity as > 5 hours/week or > 15 MET-hours/week. The team also calculated the population attributable fraction (PAF) which can be used to quantify how a risk factor contributes to the outcome of interest compared, in this case, physical inactivity and cancer.
When optimal physical activity was defined as > 15 MET-hours/week, the overall PAF for both sexes was 3% (95% CI 2.9 – 3%). This amounted to 46,356 incident cancer cases in adults aged > 30 years, that could be attributed to physical inactivity. The overall PAF was higher in women than men (4.1% vs 1.8%), with the result that 32,089 incident cancer cases in women and 14,277 cases in men were attributable physical inactivity.
With respect to the individual cancers, stomach cancer had the highest PAF (16.9%), followed by corpus uteri (11.9%), kidney (11%), colon (9.3%), oesophagus (8.1%), breast (6.5%) and bladder (3.9%). In addition, PAF values varied across the US for the different cancer. For example, the PAF for stomach cancer was 14% in Montana and 21.1% in Kentucky.
The researchers concluded that physical inactivity was a potentially avoidable cause of a large number of cancers and that promoting physical activity could prevent many cases.
Minihan AK et al. Proportion of Cancer Cases Attributable to Physical Inactivity by US State, 2013-2016. Med Sci Sports Exerc 2021