The risk for type 1 and type 2 diabetes from childhood into adulthood is increased in preterm-born individuals, according to study results published in Diabetologia.
While previous studies have reported an association between preterm birth (gestational age <37 weeks) and insulin resistance, none have examined the association between gestational age at birth and diabetes from childhood to adulthood in a large population.
To explore this, researchers used data from the Swedish Birth Registry, a national cohort study with data for more than 4 million singleton births in Sweden between 1973 and 2014, followed from birth into adulthood (median age at end of follow-up, 22.5 years).
Type 1 diabetes developed in 27,512 participants (0.7%) and type 2 diabetes in 5525 subjects (0.1%). There was an inverse association between gestational age at birth and both type 1 (adjusted hazard ratio [HR] per additional week of gestation, 0.96; 95% CI, 0.95-0.97) and type 2 diabetes (adjusted HR per additional week of gestation, 0.95; 95% CI, 0.93-0.98) before age 18 years.
Preterm birth was associated with a 21% increase in risk for type 1 diabetes developing (HR, 1.21; 95% CI, 1.14-1.28) and a 26% increase in risk for type 2 diabetes developing (HR, 1.26; 95% CI, 1.01-1.58) before 18 years of age. From age 18 to 43 years, preterm birth was associated with a 24% (HR, 1.24; 95% CI, 1.13-1.37) and 49% (HR, 1.49; 95% CI, 1.31-1.68) increased risk, respectively, compared with full-term birth.
Analysis by sex revealed that while there was no significant sex difference for type 1 diabetes, the risk for type 2 diabetes at age 18 to 43 years was significantly higher for women (HR, 1.75; 95% CI, 1.47-2.09) than for men (HR, 1.28; 95% CI, 1.08-1.53; P <.01) who were born preterm.
Co-sibling analyses suggested that shared genetic or environmental factors in families only partially explained these associations.
Compared with full-term birth, both spontaneous and medically indicated preterm birth were linked to increased risk for type 1 diabetes (adjusted HRs, 1.22 [95% CI, 1.11-1.34] and 1.22 [95% CI, 1.09-1.37], respectively) and type 2 diabetes (adjusted HRs, 1.41 [95% CI, 1.05-1.90] and 1.45 [95% CI, 1.02-2.04], respectively).
The researchers acknowledged several study limitations, including unavailable laboratory data to verify diagnoses of diabetes, possible detection bias, a relatively young cohort, and results limited to a Swedish population. The investigators suggested more studies are necessary in other countries and populations.
“Children and adults who were born prematurely may need early preventive evaluation and long-term follow-up for timely detection and treatment of diabetes,” concluded the researchers.
Crump C, Sundquist J, Sundquist K. Preterm birth and risk of type 1 and type 2 diabetes: a national cohort study [published online December 3, 2019]. Diabetologia. doi:10.1007/s00125-019-05044-z