A significant social difference between Maori and non-Maori in the study, and one that underpins health differences, is that the majority of Maori, 60 per cent, lived in areas of high deprivation. For non-Maori the proportion was 35 per cent.
The researchers hope to discover the things that help people age successfully - as happily and healthily as possible.
Driving the study is the fact that the very old consume a high proportion of New Zealand's health and disability care and are the nation's fastest growing age group. Their proportion of the population is expected to more than double by 2050, to 8 per cent.
The lead author of the journal article, general practice research fellow Dr Ruth Teh, said: "This is probably the first paper in New Zealand that describes the health status of our older people in their 80s that significantly gives more information about how they are doing ...
"We can see that they have good quality of life despite having multiple morbidities [diseases]."
Comparisons were made with studies of elderly people overseas, particularly in Newcastle, Britain.
"We found that generally our cohort in New Zealand is healthier, physically and mentally, compared to the Newcastle group. I think we are doing pretty good," said Dr Teh.
"The other main point is that there are still many areas for us to improve on the health status and the core signs of older people."
In the Newcastle 85+ study, 11 per cent rated their health as excellent when compared with others of the same age.
The number making this response was significantly higher in the Bay of Plenty/Lakes study, ranging from 20 per cent of non-Maori men to 14 per cent of Maori women.
When the question was simply how do you rate your own health, the proportion answering "excellent" ranged from 6 per cent of non-Maori men, to 3 per cent of Maori men.
Maori people were found to smoke more than non-Maori, drink alcohol less often and be more physically active.
Eleven per cent of Maori were smokers, compared with 5 per cent of non-Maori. National surveys have found smoking rates among the elderly are much lower than other adults. Last year's Census found that among those aged 15 or more, 33 per cent of Maori and 13 per cent of non-Maori smoked daily.
In the Bay/Lakes study - called "LiLACS", the Life and Living in Advanced Age Cohort Study - the ethnic smoking disparity was linked to higher rates of respiratory disease in Maori.
Maori reported drinking alcohol two or more times a week at about half the rate of non-Maori - 23 per cent compared with 47 per cent. And in both ethnic groups, women drank two or more times a week at about half the rate or less of men.
Maori men reported the highest level of physical activity, 113 points on a scale that goes to 720, slightly ahead of non-Maori men. Non-Maori women scored lowest, on 77.
Dr Teh said these were moderate levels of physical activity. Much of the exercise fell into the "household" activities category which included mowing lawns and gardening, rather than "leisure" activities such as walking the dog. This was why men, and Maori, reported higher levels than their comparison groups.
"Maori have a lot of activities to do with their marae and iwi activities that also has to do with more 'household-related' activities."
The strength of an old person's hand grip is said to be linked to their future health. Maori men in the LiLACS study had the strongest grip, at 30.8kg, slightly more than the 30.3kg of non-Maori men. Both were notably stronger than the average of 27.5kg for men in a large international study. Bay/Lakes women were also above the international norm.
In walking speed, however, the LiLACS participants were behind the world standard. A rate of 0.8 metres a second marks a significant risk of health problems. This was the average speed for Maori; for non-Maori it was even lower, at 0.7m a second.
Not eating enough nutritious food is an increasing risk for people as they age and can lead to infections, muscle loss, falls, fractures and pressure ulcers.
About 40 per cent of LiLACS participants were at high nutrition risk.
The study found a link between nutrition and driving. The rates of high nutrition risk were markedly higher among Maori and women - who were also the groups with the fewest still driving.
"Driving is an indication of being independent," said Dr Teh, "and being independent means you can go to the shops and have more variety of food."
This might be even more so in rural areas, where there was less public transport, she said.
Another nutrition factor is having trouble chewing food. It is linked to reduced physical functioning and it affected 24 per cent of those in the study, mainly because of ill-fitting dentures or missing teeth. Seventy-six per cent wore dentures.
Fewer Maori than non-Maori had visited a dentist in the previous year (18 per cent, compared with 34 per cent).
The researchers looked at hospital and doctors' records to help determine chronic disease rates. Some of the ethnic disparities they found reflect whole-of-life trends, such as the higher Maori rate of diabetes.
But the non-Maori cancer rate is nearly four times higher than the Maori rate in LiLACS, whereas for all ages, the Maori rate is the uniformly higher one among women and is mostly higher for men.
Dr Teh said the cancer finding couldn't be fully explained.
"Some factors probably include under-diagnosis (people with cancer were not identified), differential treatment and differential access to treatment result in survival selection."
This meant Maori were less likely to survive cancer, which reduced the Maori cancer rate among the elderly and hence in the study.
Dr Teh said the researchers would continue follow-up surveys with the LiLACS group for another five to 10 years.
Gordon Allan, 89
Gordon Allan attributes his long and healthy life to a good start, and nutritious food.
A healthy early childhood sets people up for a long life, says the 89-year-old from Hamilton.
"I lived in the backblocks of Poverty Bay. I had to walk a mile to school when I was young but we ate well and we had tons of exercise, tons of games to play, we made our own fun and had horses to ride.
"The most important thing is we ate well. We didn't go and get fish and chips and icecreams and chocolate and all these modern things. Kids go to the store and eat the wrong sort of foods.
"All my brothers and sisters have lived to be over 90. One is still alive, at 95, and the others [two brothers and one of his sisters] all died at 92."
Mr Allan has four living children - one died last year of cancer - plus 10 grandchildren and three great-grandchildren.
Of Scottish ancestry, he was among the 19 per cent of non-Maori in the study who rated their health as "very good", although he has had his share of heart troubles.
A retired pharmacist, he lives with Verna, his wife of 64 years and, with her help, has stuck to his philosophy of good nutrition and regular exercise.
"My wife is a very good cook," he says. "She's the mainstay of the family."
Mr Allan's emphasis on healthy eating mirrors the importance placed on good nutrition by elder-care specialists. The study found that 27 per cent of non-Maori men were at high nutrition risk.
A never-smoker, who enjoys an alcoholic drink now and then, Mr Allan goes out to watch rugby matches on Saturday afternoons.
"I go walking, usually a mile every day, at least, just to keep the muscles going, sometimes both of us, sometimes just one of us."
The couple shifted from Tauranga - where Mr Allan joined the study - to Hamilton, to be closer to family. They live in their own home, both drive, and they prize their independence.
Shirley Smith, 89
Shirley Smith is 89 and declares she is healthy and happy.
"I've got hip pain and I'll probably have to have that repaired when it's bad enough. I'm pretty good for my age; nothing much stops me from getting in the car and going off to meetings."
Shirley Smith lives in a flat at her daughter and son-in-law's house. Photo / Christine Cornege
Like 64 per cent of non-Maori women in the study, Mrs Smith, a New Zealand European, still drives.
She does voluntary work for St John as a "caring caller".
Mrs Smith, a widow, has four living children (one died in childhood), 13 grandchildren and eight great-grandchildren.
She lives independently in a flat attached to her daughter and son-in-law's house in Tauranga.
She has some arthritis, "but it doesn't worry me very much" and osteoporosis - "I have had a few falls but I haven't broken anything yet. I stumbled when I was out walking, missed the step one day."
"I've had one hip replacement. The other one is just letting me know..."
In the study, having at least one fall in the preceding 12 months was more common among non-Maori than Maori - 42 per cent compared with 35 per cent for women, and 38 per cent compared with 33 per cent for men.
Avoiding harmful falls is an important focus of safety programmes at public hospitals and rest homes, reflecting the injury-prevention strategies of the Accident Compensation Corporation and the Health Quality and Safety Commission.
Mrs Smith values her independence and has no plans to shift into a rest home, although she is not opposed to the idea when the time comes. She's not a great one for hobbies or clubs.
"My interest mainly is in church activities. We have an old people's gathering once a week and we chat about various subjects. It's very interesting.
"I'm very happy with my life."
