Data from over 140,000 people across 12 countries showed a greater proportion of adult women had poorly controlled HbA1c levels than men.
In women aged 15-29, almost three quarters had HbA1c levels of 7.5% (58mmol/mol) or over.
UK researchers behind the study, presented at the European Association for the Study of Diabetes (EASD) meeting in Barcelona this week, said the findings may be due to differences in haemoglobin levels between the sexes.
Professor Sarah Wild from the University of Edinburgh and colleagues looked at data from 142,260 adults and children with type 1 diabetes in Austria, Denmark, Germany, Italy, Latvia, New Zealand, Norway, Scotland, Slovenia, Sweden, Ukraine and the US.
The researchers examined clinical records for blood sugar readings from the past 12 to 24 months, and compared the proportion of males and females in each age group with HbA1c of 7.5% (58mmol/mol) or over.
This ranged from 64.4% in boys aged under 15 years to 74% in women aged 15-29 years.
They found no difference in control levels between boys and girls aged under 15 years. However, women aged 15-29 were 8% more likely to miss glucose targets than men of the same age. Among the over 30s, women were 6% more likely to have poor glucose control than men.
Professor Wild concludes: 'In this analysis of type 1 diabetes data from several countries, males were more likely to have a better blood sugar control profile than females. Further work is required to investigate explanations for this finding.'
She added: 'One explanation could be that women tend to have lower haemoglobin levels than men which could explain the higher HbA1c levels, but further research is required to confirm this.'
