Health trends over the last 45 years: We’re getting fatter — but healthier
Norway's most comprehensive population survey shows some surprising contradictions. The average Norwegian has gotten heavier over the last 45 years, while at the same time their overall physical health has improved.
Henrik Schirmer is gradually losing his job — and he’s happy about it.
Schirmer is a researcher and heart specialist who has worked on the Tromsø Study, Norway’s largest population-based study.
He’s seen the study results show fewer deaths from stroke, heart attack and fewer cases of diabetes since 1974, when the study began. There is also data that suggest younger people are less likely to get cancer than previous generations.
"And all this is happening at the same time as we are getting heavier and heavier, year by year," says Schirmer.
Halving mortality
The Tromsø Study shows that Norwegians' physical health has followed a remarkably positive trend.
Most importantly, the mortality rate from cardiovascular disease has been reduced by more than 80 percent over the past 50 years — which means far less work for Schirmer.
Initially, this drop in mortality was mainly because Norwegians lived healthier lives, and were less likely to have a heart attack or stroke.
“But in the last 15 years, the drop in mortality is largely due to fewer people dying if they have had a heart attack. During this period, the chance of dying from infarction has fallen by more than 50 per cent,” Schirmer says.
Much of this positive trend is due to better medication and better treatment. But not all.
Laila Hopstock, also a Tromsø Study researcher, has studied the figures thoroughly and published several scientific articles that show that blood pressure and cholesterol levels in Norwegians have dropped during the study period, including among those who do not use medication.
“Young people in Tromsø municipality also had much higher blood pressure and cholesterol 45 years ago. And they did not take medication to treat it.
So something other than medicines and better medical treatment is making us healthier. But what is it?” she asks.
People are fatter
When the Tromsø Study started in 1974, the average individual in Tromsø was what researchers call normal weight. That is, their body mass index, or BMI, was under 25. That has changed dramatically.
“We have seen tremendous weight gain during the study period. Today, being overweight is normal,” says Hopstock.
Today, an average 40-something male Tromsø resident who is 1.80 metres tall weighs 90 kilos. A female in the same age group who is 1.60 metres tall weighs an average of 73 kg.
In just the last ten years or so, the average Tromsø resident has gained nearly 200 grams every single year.
Both researchers and health professionals know that being overweight increases a person’s risk of cardiovascular disease and diabetes. But the data show that the population of Tromsø is doing well anyway, despite the fact that they have gained a lot of weight.
This raises the question: Can a person be overweight and still healthy?
Laila Hopstock thinks it's too early to give a definitive answer to this.
“We might see a new epidemic of cardiovascular disease, as happened in the 1970s. But we don’t know that yet,” she says.
60 per cent smoked
When the Tromsø survey started 45 years ago, the population of Northern Norway had the highest mortality rate of cardiovascular disease in the country.
In Finnmark, the northernmost county in the country, the proportion of men who died of cardiovascular disease was as much as 50 per cent above the national average. Tromsø, which is in Troms County, southwest of Finnmark, showed similar rates.
The three main risk factors for cardiovascular disease are, in descending order of importance, smoking, high blood pressure and high cholesterol.
All of these risk factors were soaring in Tromsø's population in the 1970s.
Many had high blood pressure and cholesterol. But now these levels have dropped considerably, as has the number of smokers.
As many as 60 per cent of people between the ages of 40 and 50 who participated in the Tromsø Study 45 years ago were smokers. Today, only 10 percent smoke daily.
“But the problem of smoking has not been solved,” says Hopstock.
Although there has been a sharp decline in the number of daily smokers, there are major social differences in terms of who smokes. The same is true for health. Those with the least education smoke the most. The researchers can’t say if the effect of the drop in the number of smokers has reached its peak. Regardless, those who smoke will have poorer health than non-smokers.
Better memories
The Tromsø Study has also looked at what scientists call cognitive function — or how well our brains work.
Here, the study findings among Tromsø’s elderly are startling.
Older study participants have been tested at three different times to see how well they remember, how fast they think and how flexible their cognitive abilities are. One example of the tests is a word test where participants are asked to remember 12 words.
Older Tromsø residents have increasingly better memories over time. Today, an 80-year-old Tromsø resident remembers as well as a 70-year-old did around the turn of the millennium.
Researchers and the medical community have long warned that dementia cases will skyrocket, as populations in Western countries age. Some have warned of a doubling of new cases in the future.
But the very good development in cognitive abilities of Tromsø’s elderly might also signal good news in terms of dementia. The significance of the trend in improved cognitive abilities remains unclear. But studies in the UK have also shown a significant drop in new cases of dementia.
Researcher Bente Johnsen will now start studying dementia, based on data from the Tromsø Study.
Now they will begin recording dementia cases. Researchers will then have new material, gathered in a population that has been studied for nearly five decades.
-----------------------------
Read the Norwegian version of this article at forskning.no
