Will I still be alive five years from now? Will you? Dare we find out? The fashionable way to do so is to take the "Ubble" test, which can - allegedly - predict your longevity. It is based on an algorithm developed by two researchers from the Swedish Karolinska Institute, Erik Ingelsson and Andrea Ganna, and it was published last week in the medical journal, 'The Lancet'.
I set myself the task of taking the Ubble test over the weekend, though I dreaded doing so. I'm strongly of the view that it's better if we don't know the future.
Yet the test is considered to be medically significant and perhaps a harbinger of future medical trends, when the human genome project will map the state of our health. Ubble merely asks men and women some predictable, and some surprising, questions. And omits some surprising ones, too. The predictable ones are obvious: do you smoke? Did you ever? (An omission is any reference to weight.)
Surprisingly, too, there are no questions about family longevity, though it is well-observed that longevity often runs in families: if you parents lived into their nineties, you have a good chance of doing so. Although, admittedly, this can be variable: one of my siblings died at 82, one at 69 and one at a very premature 52.
An obvious question posed by the Ubble test is whether you have ever been told that you have cancer.
Women are asked: "Have you ever seen a GP for nerves, anxiety, tension or depression?" Men are asked: "How many cars or vans are available to your household?" (This indicates wealth, which co-relates with better health.) Men are also asked about any history of heart attack, angina, stroke or high blood pressure, while women are asked how many children they have borne: large families put more stress on women's health.
Perhaps the most controversial issue is about walking speed. Is your walking speed slow, steady average, brisk or none of the above? If you choose "slow", it may indicate you're a goner with five years.
So I chose "steady average", although I don't always keep up with others on a group walk, and I can be a bit of a dawdler. (Does looking in shop windows count?)
The test proceeds on the assumption that the recent death of a close relative, or a spouse, marital separation or divorce, or financial troubles, will affect your longevity.
According to the researchers, the most powerful indicator of impending death in men is how they rated their overall health themselves. Ingelsson and Ganna claim that we are often the best judges of our own state of health.
I'm not sure this is true, and especially not for those of us who are hypochondriacs. People with constant resort to the medical dictionary of symptoms (or checking every twinge via Google) often have a highly pessimistic view of their health. This doesn't always turn out to be accurate. "Creaking doors last the longest," my grandmother used to say.
Although the Ubble test has been applauded by medical experts and it's an interesting exercise, it cannot be exact. It can be only a broad indicator, and there are so many exceptions to any general rule: life's events are so often unexpected.
The outcome of my test told me that my risk of dying over the next five years is 7.8pc. Well, it's always nice to pass an exam, but I wouldn't take it as gospel. I think I prefer to heed the advice of the original gospel: "You know not the day nor the hour."
Other traditions emphasise the unpredictability of life: live each day as if it were your last, say the Buddhists. It's wise to contemplate your impending death, but morbid to dwell on it.
I'm always alert to the idea that I could step under a bus at any time: and God knows, individuals have suddenly met their ends in a freak traffic accident, with the falling of a tree in a high wind, with a tragic drowning on a summer's day. I often think of Princess Diana going through those swing doors at the Paris Ritz: she cannot ever have imagined she was in her last hour.
There's another aspect of the Ubble test which isn't accounted for: you can have a long decline of faculties without actually dying, and I'm not sure if that isn't a greater affliction.
However, I guess I should look on the bright side and look forward to my 93.2pc chance of reaching 2020, focusing perhaps on walking a little more briskly.
You can take the test on: www.ubble.co.uk