Men diagnosed with type 2 diabetes (T2D) by the age of 40 years appear significantly more likely to develop retinopathy than men who are diagnosed at an older age, Norwegian researchers report.
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In a cross-sectional study of about 10,000 people, men with young-onset T2D were 72% more likely than men aged 50 years or older to have retinopathy.
While an increased retinopathy risk was also seen in women with young-onset T2D versus older women at first, this difference was not significant after adjusting for various confounding factors.
The effect of young-onset diabetes on retinopathy seems to be gender specific, Katrina Tibballs, MD, of the department of general practice at the University of Oslo, reported at the annual meeting of the European Association for the Study of Diabetes.
“In the unadjusted analysis, the odds ratio for retinopathy was substantially higher in both [young-onset] men [odds ratio, 3.0] and women [OR, 2.46], compared with those 50 or older at diabetes diagnosis,” Dr. Tibballs said.
That relationship was not substantially altered after adjustment for variables such as level of education, country background, gender, and body mass index, with adjusted ORs of 2.56 and 2.55 for men and women, respectively.
However, further adjustment to include current age, duration of diabetes, and blood lipids and glycated hemoglobin levels, led to the difference no longer holding for women (OR, 1.34; 95% confidence interval, 0.95-1.89) as it did for men (OR 1.72; 95% CI, 1.29-2.29).
First data in Norwegian population
Cross-sectional data on more than 10,000 people with T2D were used for the analysis. These came from the ROSA4 study, a general practice study conducted across Norway in 2014.
Just over 10% of the study population used in the analysis was under the age of 40 years at diagnosis of T2D; 21% were aged between 40 and 49 years, and 69% were at least 50 years old.
The mean age of those with young-onset T2D, defined as a diagnosis before the age of 40 years, was 33 years. These individuals had a longer disease duration than those in the other age groups (11.4 vs. 10.0 vs. 7.8 years).
“Looking at clinical characteristics, we say that individuals [with young-onset T2D] have a higher level of hemoglobin A1c than those with diabetes onset later in life,” Dr. Tibballs said.
“This is despite a substantially higher proportion [being] treated with insulin and fewer on lifestyle interventions alone.”
Gender differences were seen in A1c levels, with men with young-onset T2D having consistently higher levels than women, with levels increasing with diabetes duration.
Rise in retinopathy faster in men than in women
Dr. Tibballs reported that, not only did the prevalence of retinopathy rise faster in those of a younger age, but it also rose more quickly in men with young-onset T2D than it in their female counterparts.
“Comparing that [young-onset diabetes] and later-onset diabetes in men and women separately, we see a clearly higher prevalence of retinopathy with increasing diabetes duration for [young-onset] men,” she said.
In women, on the other hand, there was “no clear indication of a higher retinopathy prevalence in [young-onset diabetes], except in those with the longest diabetes duration.”
So, what do the results mean for practice? First, they confirm prior work showing that there is a strong association between retinopathy and age at diagnosis of T2D. Second, they suggest that this is despite intensive glucose-lowering treatment.
She speculated that men with young-onset T2D may have had a delayed diagnosis when compared with women and individuals with later onset diabetes, Dr. Tibballs said.
“This may in turn lead to delayed onset of glucose-lowering treatment, allowing for more time with high glycemic exposure and increased risk of acquiring complications, such as retinopathy at the time of diagnosis, or in the first years after,” said Dr. Tibballs.
These are cross-sectional data, “so we can’t say anything about whether this treatment is sufficient, but it is obviously not reducing HbA1c levels as much as we would like” added Dr. Tibballs, who is a primary care physician and PhD student.
The study was supported by The Norwegian Research Fund for General Practice. Dr. Tibballs had no conflicts of interest to disclose.