In
a busy, terraced house in Bradford, three sisters are animatedly
chatting. It's a big day at their home: a beautician sits on their sofa,
styling their hair and makeup. The room is warm with fun and laughter.
It feels like a scene from a Jane Austen novel: three women in their
late 20s, each of them bursting with personality, swapping stories.
And like most Austen novels, the conversation often turns to marriage.
The
sisters are preparing for a family wedding at the weekend - where the
bride and groom are first cousins. Many people might find this unusual,
but in their family and in some parts of Bradford, it's fairly common.
Ayesha,
who at 29 is the oldest of the three sisters, also married her first
cousin in 2017. She has two children with her husband and their marriage
is happy, she says. It felt perfectly normal at the time to marry her
cousin. Their mother, a Pakistani migrant, assumed it was what all three
of her daughters would do.
But
26-year-old Salina, the youngest of the three, tells us she broke the
mould by having what they call a "love" marriage, choosing a partner
from outside the family. Salina tells us she is outgoing and ambitious;
marrying a cousin simply did not appeal to her. Then there's Mallika,
who at 27 is the middle of the three. She's still single and has already
decided not to marry within her family.
"I
said to my mum that I wouldn't judge my sisters but I wasn't going to
do it," Mallika tells us. She says having an education has created
opportunities for her. "Before, even if you had an education, you
wouldn't be expected to carry on with it. You would be thinking of
marriage. Now the mindset is so different."
Worrying new data
Researchers at the city's university are entering their 18th year of the Born in Bradford study.
It's one of the biggest medical trials of its kind: between 2007 and
2010, researchers recruited more than 13,000 babies in the city and then
followed them closely from childhood into adolescence and now into
early adulthood. More than one in six children in the study have parents
who are first cousins, mostly from Bradford's Pakistani community,
making it among the world's most valuable studies of the health impacts
of cousin marriage.
And in data
published in the last few months - and analysed in an upcoming episode
of BBC Radio 4's Born in Bradford series - the researchers found that
first cousin-parentage may have wider consequences than previously
thought.
The most obvious way that a
pair of blood-related parents might increase health risks for a child is
through a recessive disorder, like cystic fibrosis or sickle cell
disease. According to the classic theory of genetics laid out by the
biologist Gregor Mendel, if both parents carry a recessive gene then
there's a one in four chance that their child will inherit the
condition. And when parents are cousins, they're more likely to both be
carriers. A child of first cousins carries a 6% chance of inheriting a
recessive disorder, compared to 3% for the general population.
But
the Bradford study took a much broader view - and sheds fresh light.
The researchers weren't just looking at whether a child had been
diagnosed with a specific recessive disorder. Instead they studied
dozens of data points, observing everything from the children's speech
and language development to their frequency of healthcare to their
performance at school. Then they used a mathematical model to try to
eliminate the impacts of poverty and parental education - so they could
focus squarely on the impact on "consanguinity", the scientific word for
having parents who are related.
hey found that even after factors like
poverty were controlled for, a child of first cousins in Bradford had an
11% probability of being diagnosed with a speech and language problem,
versus 7% for children whose parents are not related.
They
also found a child of first cousins has a 54% chance of reaching a
"good stage of development" (a government assessment given to all five
year-olds in England), versus 64% for children whose parents are not
related.
We get further insight into
their poorer health through the number of visits to the GP. Children of
first cousins have a third more primary care appointments than children
whose parents are not related - an average of four instead of three a
year.
What is notable is that even
once you account for the children in that group who already have a
diagnosed recessive disorder, the figures suggest consanguinity may be
affecting even those children who don't have a diagnosable recessive
disorder.
Neil Small, emeritus professor at the University of Br
adford
and the author of the study, says that even if all of the children with
recessive disorders visited their GP more than average, "this does not
explain the much wider distribution of excess health care usage in the
consanguineous children".
The study,
he says, is "exciting because it gives the opportunity for a much more
accurate development of a response, targeting interventions and
treatments"
(Continue)
