Baby X is born in a Canadian hospital and her tiny, wrinkled body is placed on a scale that reads 3,061 grams, or 6 pounds and 12 ounces.
Things can go one of two ways for Baby X, whose parents are immigrants from India.
According to the standard birth-weight curves used in Canada, which are modelled after norms for Caucasian newborns, this baby could be labelled as underweight, a classification that comes with a higher risk of death and lower cognitive ability. She could be subjected to a battery of unnecessary tests and follow-ups. Her concerned mother might overfeed her in hopes of speeding up her growth.
Or, if a new birth-weight curve developed at Toronto’s St. Michael’s Hospital – one that takes into account a wide range of ethnicities – is used, Baby X will be classified as having a perfectly normal weight and will be sent home. South Asian newborns are typically smaller than those of many other ethnicities.
It’s just one example of why there is a move in Canada and other countries to collect data on their diverse populations to deliver better patient care.
Doctors and researchers are putting greater stock in ethnicity as a variable in health outcomes. A large body of research suggests certain groups are at a higher genetic risk for particular diseases. And physiologically, what is accepted as “normal” and “healthy” varies between ethnicities.
But there are no universal standards or terms of reference used to classify ethnicity, which has made it a highly fraught subject. Some say it shouldn’t be considered a variable at all, arguing that the link between ethnicity and health is manufactured. The Canadian Institute for Health Information doesn’t collect data on ethnicity, and the Canadian Medical Association has no formal policy on the best way to classify the diverse backgrounds of Canadians.
Joel Ray, who led the St. Michael’s Hospital team that developed the new newborn birth-weight curve, is baffled that an old model developed in 1969 based on the weights of 300 Caucasian newborns in Montreal – a population unreflective of modern Canada – is still used in some parts of the country. In a study published Wednesday in the Journal of Obstetrics and Gynaecology Canada, his team analyzed 760,000 live births in Ontario and, by their measure, more than one in 10 South Asian babies was at risk of being misclassified if one of the standard Canadian birth-weight curves was used.
“They’re completely archaic – there’s no other sweet word for it,” Dr. Ray said.
Dr. Ray previously studied rates of gestational diabetes among women of various ethnic groups and found South Asians had the highest risk levels, followed by those from East Asia and the Middle East. Previous studies have lumped these three groups together under the catch-all category “Asian” – missing the heterogeneity within.
“You may as well call them human if you’re going to call someone Asian,” he said.
It seems even a breakdown by subcontinent isn’t precise enough.
In 2008, a team of New York researchers studied the rates of gestational diabetes among New York City’s population with a breakdown by country of origin. The results revealed much heterogeneity within sub-regions: While women from Bangladesh (classified as part of Southeast Asia) had a 7.1-per-cent risk of developing gestational diabetes, those in Iran (part of the same subcontinent) had only a 1.3-per-cent risk.
Sonia Anand, Canada Research Chair in ethnic diversity and cardiovascular disease at McMaster University, says the way she classifies ethnicity has greatly evolved in the last two decades. Dr. Anand runs genetic analyses on individuals she studies and asks them to list their ethnicity, as well as that of their parents and grandparents.
The wording is key: Dr. Anand asks for ancestral country of origin to allow for migration – for example, a large population of Indians has lived for generations in Trinidad.
Some researchers also use surname databases to determine ethnicity, but that’s an imprecise system, Dr. Ray points out. “Lee” can be a Chinese name, but also an Anglo one. “De Souza” is a common surname for both the Portuguese and Goan Indians.
