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Following Forward: Forty Thousand Doctors and Fifty Years · Truth in Motion with Dr. Jocelyn

• 0:02
  SPEAKER_00: Welcome to Truth in Motion with Dr.
• 0:05
  SPEAKER_00: Jocelyn, where insight, clarity, and wisdom help you thrive.
• 0:10
  SPEAKER_00: Thank you for joining me.
• 0:12
  SPEAKER_00: Yesterday, we looked back.
• 0:15
  SPEAKER_00: We sat in on Dalin Hill's study in 20 London hospitals where patients with lung cancer were compared with patients without it, and smoking stood out.
• 0:27
  SPEAKER_00: We saw eight young women in Boston and a drug called DES.
• 0:32
  SPEAKER_00: And we saw how our poorly chosen comparison group made coffee look guilty.
• 0:38
  SPEAKER_00: We left with three questions for any linked to headline.
• 0:43
  SPEAKER_00: How did they find out what people did?
• 0:46
  SPEAKER_00: Who were they compared with?
• 0:49
  SPEAKER_00: Is this a pattern or a proof?
• 0:52
  SPEAKER_00: Today we turn around and face the other way.
• 0:55
  SPEAKER_00: We follow people forward.
• 0:58
  SPEAKER_00: This kind of study is called a prospective study.
• 1:02
  SPEAKER_00: The classic kind is the cohort study.
• 1:05
  SPEAKER_00: We'll meet 40,000 British doctors who agreed to be watched for the rest of their lives.
• 1:11
  SPEAKER_00: We'll visit a small town in Massachusetts that has helped teach the world about the heart for more than 70 years.
• 1:18
  SPEAKER_00: And we'll see the one weakness that even the biggest of these studies can't escape.
• 1:25
  SPEAKER_00: Why does this matter?
• 1:26
  SPEAKER_00: Because much of the health advice we live by today came from following people forward.
• 1:33
  SPEAKER_00: Don't smoke, watch your blood pressure, keep moving.
• 1:36
  SPEAKER_00: Those aren't guesses.
• 1:38
  SPEAKER_00: They came from watching real people, year after year, and seeing who stayed well and who didn't.
• 1:45
  SPEAKER_00: But this kind of study has also given us advice that later had to be taken back.
• 1:50
  SPEAKER_00: And when that happens, many of us stop trusting health advice altogether.
• 1:55
  SPEAKER_00: We think they keep changing their minds.
• 1:58
  SPEAKER_00: Why listen at all?
• 1:59
  SPEAKER_00: When we understand how following forward works, we don't have to swallow everything and we don't have to throw everything out.
• 2:07
  SPEAKER_00: We can see why some advice stands for 50 years and why some just falls apart.
• 2:13
  SPEAKER_00: That's what today is for.
• 2:16
  SPEAKER_00: The word cohort comes from the Roman army.
• 2:19
  SPEAKER_00: A cohort was a unit of soldiers who marched together.
• 2:23
  SPEAKER_00: In medicine, a cohort is a group of people we follow together through time.
• 2:29
  SPEAKER_00: Here's how it works: we gather a large group of people before they get sick.
• 2:35
  SPEAKER_00: We record their habits, what they eat, whether they smoke, how they live, and then we wait.
• 2:41
  SPEAKER_00: We follow them for years, sometimes decades, and we watch who develops what.
• 2:48
  SPEAKER_00: Notice the difference from yesterday?
• 2:50
  SPEAKER_00: Looking back, we started with the disease and searched people's memory.
• 2:55
  SPEAKER_00: Following forward, we record the habit first.
• 2:59
  SPEAKER_00: While everyone is still well, no one has to remember anything.
• 3:03
  SPEAKER_00: The habit is written down before anyone knows how the story ends.
• 3:08
  SPEAKER_00: The price is patience.
• 3:10
  SPEAKER_00: Sometimes a whole career of it.
• 3:14
  SPEAKER_00: After their 1950 study, Dalin Hill knew what their critics would say.
• 3:20
  SPEAKER_00: A looking back study shows a pattern.
• 3:22
  SPEAKER_00: It can't prove a cause.
• 3:24
  SPEAKER_00: Memories bend.
• 3:26
  SPEAKER_00: Comparison groups can be wrong.
• 3:28
  SPEAKER_00: So they decided to do it the hard way.
• 3:32
  SPEAKER_00: In October of 1951, they sent out a short questionnaire to 59,600 doctors on the British Medical Register.
• 3:42
  SPEAKER_00: Do you smoke?
• 3:44
  SPEAKER_00: What?
• 3:44
  SPEAKER_00: How much?
• 3:45
  SPEAKER_00: Since when?
• 3:47
  SPEAKER_00: More than 41,000 doctors wrote back.
• 3:51
  SPEAKER_00: Why doctors?
• 3:52
  SPEAKER_00: Because doctors are easy to keep track of.
• 3:55
  SPEAKER_00: Their names stay on the medical register year after year, wherever they move.
• 4:00
  SPEAKER_00: Then Dal and Hill waited.
• 4:03
  SPEAKER_00: They didn't have to wait long for the first signal.
• 4:06
  SPEAKER_00: In 1954, about two and a half years in, they published their first report.
• 4:12
  SPEAKER_00: Among the men over 35, the more a doctor smoked, the higher his risk of dying from lung cancer.
• 4:21
  SPEAKER_00: The same pattern they had found by looking back now appeared looking forward in a completely different group of people.
• 4:29
  SPEAKER_00: That's what makes evidence strong.
• 4:31
  SPEAKER_00: Not one study, two different methods pointing the same way.
• 4:36
  SPEAKER_00: And notice one more thing: it wasn't just smokers versus nonsmokers.
• 4:41
  SPEAKER_00: The more a doctor smoked, the higher the risk climbed.
• 4:45
  SPEAKER_00: Light smokers, more, heavy smokers more still.
• 4:50
  SPEAKER_00: When a risk rises step by step with the dose, that's called a dose response.
• 4:57
  SPEAKER_00: And it's one of the strongest signs that we're looking at something real, not just a coincidence.
• 5:05
  SPEAKER_00: And they kept going.
• 5:07
  SPEAKER_00: The doctors were sent new questionnaires in 1957, 1966, 1971, 1978, 1991, and 2001.
• 5:20
  SPEAKER_00: Richard Dull followed his doctors for 50 years.
• 5:25
  SPEAKER_00: Think about what that took.
• 5:27
  SPEAKER_00: Half a century of letters, records, and patients.
• 5:32
  SPEAKER_00: Thousands of doctors answering the same questions again and again, long after the first excitement had worn off.
• 5:40
  SPEAKER_00: Most research careers don't last that long.
• 5:43
  SPEAKER_00: In 2004, he and his colleagues published the 50-year results on 34,439 men.
• 5:53
  SPEAKER_00: Here's what they found.
• 5:55
  SPEAKER_00: The men who smoked cigarettes and kept smoking died, on average about 10 years younger than men who had never smoked.
• 6:04
  SPEAKER_00: 10 years.
• 6:06
  SPEAKER_00: But here's the part I want you to hear.
• 6:08
  SPEAKER_00: Quitting made a difference at every age.
• 6:11
  SPEAKER_00: Men who stopped at 60 gained about three years of life.
• 6:15
  SPEAKER_00: Stopping at 50 gained about six.
• 6:19
  SPEAKER_00: Stopping at forty gained about nine.
• 6:21
  SPEAKER_00: And men who stopped at 30 gained about 10 years.
• 6:25
  SPEAKER_00: Nearly the whole loss.
• 6:27
  SPEAKER_00: Undone.
• 6:29
  SPEAKER_00: That's hope backed by numbers.
• 6:32
  SPEAKER_00: The body heals when we give it the chance, and no looking back study could ever have shown it, because it took 50 years of watching to see.
• 6:45
  SPEAKER_00: Now let's cross the ocean to a town about 20 miles west of Boston.
• 6:50
  SPEAKER_00: In April of 1945, President Franklin Roosevelt died of a stroke.
• 6:57
  SPEAKER_00: His blood pressure had been measured as high as 300 over 190.
• 7:02
  SPEAKER_00: At the time, there was little anyone thought to do about it.
• 7:06
  SPEAKER_00: Heart disease was killing Americans in huge numbers, and no one knew clearly why.
• 7:12
  SPEAKER_00: In 1948, the U.S.
• 7:14
  SPEAKER_00: government funded a study to find out.
• 7:16
  SPEAKER_00: They chose Framingham, Massachusetts, partly because the local doctors were eager to help.
• 7:24
  SPEAKER_00: They enrolled 5,209 men and women between 30 and 62 who had never had a heart attack or a stroke.
• 7:33
  SPEAKER_00: And every two years they came back to be examined.
• 7:38
  SPEAKER_00: In 1957, the first major findings came in.
• 7:42
  SPEAKER_00: People with blood pressure of 160 over 95 or higher had nearly four times as much coronary heart disease.
• 7:52
  SPEAKER_00: Later came the links with smoking, cholesterol, inactivity, and weight.
• 7:58
  SPEAKER_00: In 1961, the study helped bring a new phrase into medicine, risk factor, and Framingham kept going.
• 8:07
  SPEAKER_00: In 1971, it enrolled the children of the original volunteers.
• 8:12
  SPEAKER_00: In 2002, their grandchildren.
• 8:15
  SPEAKER_00: Three generations of one town helping all of us understand our own hearts.
• 8:22
  SPEAKER_00: Every time a practitioner takes your blood pressure and talks with you about what it means, that conversation stands on Framingham.
• 8:31
  SPEAKER_00: So why follow forward?
• 8:33
  SPEAKER_00: Why is following forward stronger than looking back?
• 8:37
  SPEAKER_00: First, the habit is recorded before the disease appears.
• 8:41
  SPEAKER_00: That removes the problem of memory and it shows us which came first, and that matters.
• 8:47
  SPEAKER_00: If the habit comes first, it at least could be a cause.
• 8:52
  SPEAKER_00: If it came later, it can't be.
• 8:54
  SPEAKER_00: Second, one cohort can answer many questions.
• 8:58
  SPEAKER_00: Dahl and Hill set out to study lung cancer, and they found smoking linked to heart attacks too.
• 9:05
  SPEAKER_00: Framingham set out to study the heart, and it was studied far more since.
• 9:10
  SPEAKER_00: Third, it can show us time, not just whether something happens, but how long it happens and what happens when people change, like those doctors who quit.
• 9:21
  SPEAKER_00: Now for the weak spots, because there are real ones.
• 9:25
  SPEAKER_00: The first is time and cost.
• 9:28
  SPEAKER_00: These studies take years and often decades.
• 9:32
  SPEAKER_00: Many of the people who start them don't live to see the end.
• 9:35
  SPEAKER_00: Richard Dahl was 39 when his doctor's study began, and in his 90s when the 50-year report came out.
• 9:43
  SPEAKER_00: And it's expensive to keep track of tens of thousands of people for that long.
• 9:49
  SPEAKER_00: The second is losing people.
• 9:52
  SPEAKER_00: Over the years, people move, they stop answering, or they just drop out.
• 9:57
  SPEAKER_00: And the people who drop out may not be like the ones who stay.
• 10:02
  SPEAKER_00: If the sickest people quit answering, the results can look better than the truth.
• 10:08
  SPEAKER_00: And the third weak spot is the biggest one.
• 10:11
  SPEAKER_00: It's a cohort study.
• 10:13
  SPEAKER_00: People choose their own habits.
• 10:16
  SPEAKER_00: The researchers don't decide who smokes and who doesn't.
• 10:20
  SPEAKER_00: People decide for themselves.
• 10:22
  SPEAKER_00: And people who choose one habit often differ in other ways too.
• 10:26
  SPEAKER_00: Think about it.
• 10:28
  SPEAKER_00: People who take a daily walk may also eat more vegetables.
• 10:31
  SPEAKER_00: They may sleep better, drink less, see their doctor more often, and have more money and more time.
• 10:38
  SPEAKER_00: So if walkers live longer, is it the walking?
• 10:41
  SPEAKER_00: Or is it everything else that travels along with the walking?
• 10:45
  SPEAKER_00: Researchers try to adjust for those other differences.
• 10:49
  SPEAKER_00: They measure what they can and they correct for it with statistics.
• 10:53
  SPEAKER_00: But they can only adjust for what they thought to measure.
• 10:57
  SPEAKER_00: Some differences are never measured at all.
• 11:00
  SPEAKER_00: That's why a cohort study, even a huge one, still shows a strong pattern, not a final proof.
• 11:08
  SPEAKER_00: For smoking, the pattern was so strong and so consistent and so repeated in study after study that it stood.
• 11:16
  SPEAKER_00: But not every pattern is that strong.
• 11:19
  SPEAKER_00: So here's what this gives us.
• 11:21
  SPEAKER_00: When we hear researchers followed thousands of people for years, we can ask three questions.
• 11:28
  SPEAKER_00: First, how many people and for how long?
• 11:32
  SPEAKER_00: A few hundred people for one year tells us much less than tens of thousands for decades.
• 11:39
  SPEAKER_00: Second, did people choose the habit?
• 11:42
  SPEAKER_00: And if they did, how else might they be different?
• 11:45
  SPEAKER_00: This is the big one.
• 11:47
  SPEAKER_00: Ask it every time.
• 11:49
  SPEAKER_00: Third, has the same pattern shown up in other studies, done in other ways?
• 11:55
  SPEAKER_00: Dahl and Hill's findings stood because looking back and following forward both pointed the same way.
• 12:03
  SPEAKER_00: These questions don't make us cynical, they make us wise.
• 12:07
  SPEAKER_00: We can take what a cohort study shows to heart and still remember what it can't show.
• 12:13
  SPEAKER_00: There's one more thing I want to leave with you, because following forward isn't only for researchers.
• 12:19
  SPEAKER_00: We can do it in our own lives.
• 12:22
  SPEAKER_00: Most of us, when something goes wrong with our health, we look back.
• 12:26
  SPEAKER_00: When did this start?
• 12:27
  SPEAKER_00: What did I eat?
• 12:29
  SPEAKER_00: What changed?
• 12:30
  SPEAKER_00: And we've seen how memory bends.
• 12:32
  SPEAKER_00: We remember the dramatic day and we forget the ordinary ones.
• 12:37
  SPEAKER_00: But we can also follow ourselves forward.
• 12:40
  SPEAKER_00: Write down how much you sleep, what you eat, how your energy feels, how much pain you have today.
• 12:46
  SPEAKER_00: Before you know how the story ends, then keep writing a few lines a day.
• 12:52
  SPEAKER_00: After a few weeks, you have something no memory can give you, a record.
• 12:57
  SPEAKER_00: You can see what came first.
• 12:59
  SPEAKER_00: You can see what changes when you change something, and you'll have something valuable to bring to anyone who cares for you.
• 13:07
  SPEAKER_00: Not, I think it's been worse lately, but here's what I wrote down day by day.
• 13:12
  SPEAKER_00: That's a cohort of one, and it starts with a notebook.
• 13:17
  SPEAKER_00: This week we keep questioning one layer deeper.
• 13:20
  SPEAKER_00: Here's today's practice.
• 13:22
  SPEAKER_00: Watch for one health claim this week that says people were followed or tracked over time.
• 13:29
  SPEAKER_00: Then ask the big question: Did people choose this habit?
• 13:33
  SPEAKER_00: And what else might be different about the people who choose it?
• 13:37
  SPEAKER_00: You don't need the answer, just asking it will change how you hear the next headline.
• 13:42
  SPEAKER_00: And you may find yourself asking it about your own life too.
• 13:46
  SPEAKER_00: What else changed when I started feeling better?
• 13:50
  SPEAKER_00: Today we followed people forward, we met 40,000 British doctors who let themselves be watched for 50 years and learned that smokers died about 10 years younger, and that quitting at any age gave years back.
• 14:05
  SPEAKER_00: We visited Framingham, where three generations taught us about blood pressure and the heart, and gave medicine the phrase risk factor.
• 14:14
  SPEAKER_00: And we saw the weakness even the biggest cohort can't escape.
• 14:19
  SPEAKER_00: People choose their own habits, and people who choose one thing often differ in many others.
• 14:26
  SPEAKER_00: And we saw that we can follow ourselves forward too, with a notebook and a few lines a day.
• 14:33
  SPEAKER_00: And we saw why it matters.
• 14:35
  SPEAKER_00: Much of the advice we live by came from following people forward.
• 14:40
  SPEAKER_00: When we know how it works, we can trust what deserves trust and question what doesn't.
• 14:46
  SPEAKER_00: Tomorrow we meet the fix for that weakness.
• 14:50
  SPEAKER_00: What if instead of letting people choose, we let chance decide?
• 14:55
  SPEAKER_00: We'll look at a huge study of American nurses that seemed to show one thing and a trial that showed the opposite.
• 15:02
  SPEAKER_00: And we'll look at what trials actually show about acupuncture, cranial sacral therapy, and nutrition.
• 15:09
  SPEAKER_00: I'll meet you there.
• 15:13
  SPEAKER_00: Keep the conversation going.
• 15:15
  SPEAKER_00: Find your next steps in Notes from a Fellow Traveler, my blog.