Combining three affordable public health interventions could reduce cancer risk in healthy adults aged 70 or over, new research suggests.
Researchers have found that a combination of high-dose vitamin D, omega-3s and a simple home strength exercise program (SHEP) indicated a possible cumulative reduction of 61% in cancer risk in healthy adults aged 70 or older.
The findings, published in Frontiers of Aging, were based on a trial called DO-HEALTH that was conducted over a three-year period across Switzerland, France, Germany, Austria and Portugal. The research targeted 2,157 participants who were generally healthy adults.
As part of the inclusion criteria, participants had not experienced a major health event – including a cancer diagnosis, recurrence or treatment – in the five years prior to enrolment.
They also needed to be sufficiently mobile to come to the study centres and have good cognitive function with a Mini-Mental State Exam (MMSE) score of at least 24. .
The participants were randomised into eight different groups to test the individual and combined benefit of the interventions:
- Group one received 2,000 IU of vitamin D3 per day (200% more than the current recommendations for older adults), 1g of omega-3s per day and completed a SHEP three times a week
- Group two received vitamin D3 and omega-3s
- Group three received vitamin D3 and SHEP
- Group four received omega-3s and SHEP
- Group five received vitamin D3 alone
- Group six received omega-3s alone
- Group seven received SHEP alone
- Group eight received a placebo.
All participants received check-up phone calls every three months and had standardised examinations of health and function in the trial centres at baseline, year one, year two and year three.
‘Our aim was to test promising combined interventions for cancer prevention taking advantage of potentially small additive benefits from several public health strategies,’ Dr Heike Bischoff-Ferrari, the study’s lead author from the University Hospital Zurich said.
‘In fact, novel cancer treatments aim to block multiple pathways for cancer development by combining several agents. We translated this concept into cancer prevention.’
Cancer is the second leading cause of mortality in older adults in Australia and the chances of getting most cancers increases with age.
Apart from preventative recommendations such as not smoking and sun protection, public health efforts that focus on cancer prevention are limited, according to Dr Bischoff-Ferrari.
‘Preventive efforts in middle-aged and older adults today are largely limited to screening and vaccination efforts,’ she said.
Previous mechanistic studies have shown that vitamin D inhibits the growth of cancer cells. Similarly, omega-3 may inhibit the transformation of normal cells into cancer cells and exercise has been shown to improve immune function and decrease inflammation, which may help in the prevention of cancer.
However, there is a lack of robust clinical studies proving the effectiveness of these three simple interventions, alone or combined, with the researchers attempting to address that gap.
The trial results demonstrate that all three treatments had cumulative benefits on the risk of invasive cancers.
Each of the treatments had a small individual benefit but, when all three treatments were combined, the benefits became statistically significant. The researchers saw an overall reduction in cancer risk by 61%.
‘This is the first randomised controlled trial to show that the combination daily vitamin D3, supplemental marine omega-3s, and a simple home exercise program may be effective in the prevention of invasive cancer among generally healthy and active adults aged 70 and older,’ Dr Bischoff-Ferrari said.
The results may impact the future of invasive cancer prevention in older adults, according to Dr Bischoff-Ferrari.
‘Our results, although based on multiple comparisons and requiring replication, may prove to be beneficial for reducing the burden of cancer,’ she said.
Further research is required, nonetheless.
The study authors acknowledge that the duration of the trial was short and that many years may be required to see the effects of decreasing exposure involved in the early stages of carcinogenesis.
Moreover, ‘any new invasive cancer was a pre-defined exploratory outcome and with 2,157 participants, the size of our trial may be considered small for a cancer endpoint trial, which explains the definition of cancer as an exploratory endpoint in DO-HEALTH,’ the report states.
Similarly, with regard to individual cancers, the numbers are too low to draw any reliable interpretations.
‘Future studies should verify the benefit of combined treatments in the prevention of cancer, also extending to longer follow-ups beyond the three-year duration assessed in this trial,’ Dr Heike Bischoff-Ferrari said.
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