Marilyn Palmer and her husband decamped from Vancouver five years ago.

"We had this vague notion that we would love to be out of the city in something more rural, maybe with a bit of a hobby farm," says Ms. Palmer, 69, a former architect.

Around that time, they went on a drive through the Cowichan Valley and came across a beautiful old barn that had been converted into a house, overlooking a lake, tranquil fields, and ancient Garry oaks. It was love at first sight.

Story continues below advertisement

That choice made Ms. Palmer and her partner, Phil Boname, part of the net loss of around 3,385 baby boomers from the region – the only age group that saw a net loss, between the tides of people coming in and the tides going out, according to an analysis done by University of British Columbia sociology professor Nathanael Lauster.

Their departure is seen as a potential advantage for the region in one way, and a gaping hole in other ways.

"It means less people for volunteering, less people supporting arts-and-culture institutions," says Penny Gurstein, director of UBC's school of community and regional planning. "Look at the opera now in Vancouver: there just aren't enough people in that cohort to support it."

Ms. Palmer concurs, saying that people such as her are at the peak of their volunteering activity. She is involved with four different groups in the Cowichan Valley, including one immigrant group and one focused on shelter for victims of domestic violence.

"That's a resource that I think would be lost to Vancouver," Ms. Palmer said.

On the other hand, demographer Andrew Ramlo said the departure of baby boomers means that some housing space, desperately needed in Vancouver for younger generations, is liberated. "I would hope it would free up some traditional family dwellings, either for another family or for potential redevelopment that could add a unit. I see it as positive in that sense."

While the focus is often on the supposed evaporation of children, millennials or Gen Xers, Prof. Lauster's forensic look at recently released census numbers doesn't see the changes among those groups as the crisis that they are sometimes portrayed as.

Story continues below advertisement

Vancouver is a big university city and job centre that attracts a huge number of people in their 20s, creating a demographic bulge in that age group, says Prof. Lauster, who analyzes census numbers by following cohorts through the years. That means he looks at, for example, how many 25- to 29-year-olds are in the region in 2016 compared to the number of 20- to 24-year-olds there were in 2011.

That produces results that are different than comparisons of the same age group in 2011 and 2016.

Prof. Lauster's analysis shows that some of the 35-plus group eventually moves out of the core city of Vancouver, but stays in the region. And even the city retains a significant number of the late-30s and 40s groups.

"The tidal wave of young people moving into Vancouver overcomes the slow leak of them into the region in later years," he says.

(The demographics of the urban core typically get more scrutiny in Vancouver than any other city because it is the only major Canadian city where the central city is a separate municipality. Other major cities are amalgamated, so it's difficult to track the changing demographics of the core compared to the region.)

What Prof. Lauster sees as the bigger change is the loss of older people. "If there's any leak in the metro area, it's in this baby-boomer range and it's affecting other metro areas," he says.

Story continues below advertisement

That's something that generally jives with the analysis of Mr. Ramlo, the former director of the Urban Futures Institute who is now working with Rennie Marketing. He says it's a recurring pattern.

"That 55-plus group declining in the region goes back to 1991," says Mr. Ramlo, who notes that the leakage of the 35-plus group from the city into the region is also a 25-year pattern.

But the movement of the older group accelerates as real-estate prices go up.

Chris Bradshaw and his wife had always thought they would retire to Vancouver Island. That's where he grew up and even served for a time on a municipal council.

But this past year, when a job came up with his union in Victoria, Mr. Bradshaw, 60, decided it might make sense to move five years earlier than planned. He sold his house in Port Coquitlam for close to $900,000 and bought in Langford for $200,000, which made the move that much more attractive.

He finds himself now surrounded by people who have also cashed out of the Lower Mainland and moved to the Victoria area, which has turned up the temperature on the real-estate market there.

Story continues below advertisement

"People are realizing that they can take advantage of the equity in their homes and have a better quality of life," he says.

Mr. Bradshaw, similar to Ms. Palmer, acknowledges somewhat ruefully that the city loses something when its older generation starts leaving. Yes, he says, it opens up some jobs for younger people in the bigger city, though that would happen eventually.

On the other hand, "you've got a lot of people with job, life, community experience taking all of that with them."