High prevalence of lactose absorbers in Northern Sardinian patients with type 1 and type 2 diabetes mellitus.
BACKGROUND
Increased intestinal lactase activity has been shown to occur in alloxan and streptozotocin diabetic rats.


OBJECTIVE
The objective of this study was to determine whether increased intestinal lactase activity is present in humans with diabetes mellitus.


METHODS
We assessed the capacity to digest lactose by measuring breath-hydrogen production after oral administration of lactose in 50 patients with type 1 diabetes, 50 patients with type 2 diabetes, and 50 healthy control subjects from Sassari, Sardinia, Italy, a population characterized by a low prevalence of lactase persistence (lactose absorbers).


RESULTS
Fourteen percent of control subjects were lactose absorbers, compared with 48% of patients with type 1 diabetes and 52% of patients with type 2 diabetes (P < 0.005). The odds ratio of lactase persistence in patients with type 1 diabetes was 5.3 (95% CI: 2.0, 14.0) and in patients with type 2 diabetes was 5.5 (95% CI: 2.1, 14.5).


CONCLUSIONS
Diabetes is associated with increased intestinal lactase activity in humans. Consequently, there is a greater exposure to glucose and galactose in diabetic patients with high lactose consumption. This may explain the association between diabetes and the risk of cataract.
Meloni
G F
GF
Department of Paediatrics and Neonatology and the Department of Internal Medicine, University of Sassari, Sassari, Italy.
Colombo
C
C
La Vecchia
C
C
Pacifico
A
A
Tomasi
P
P
Ogana
A
A
Marinaro
A M
AM
Meloni
T
T
D000328:Adult; D001944:Breath Tests; D016022:Case-Control Studies; D002386:Cataract / Q000209:etiology; D003922:Diabetes Mellitus, Type 1 / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D005260:Female; D006801:Humans; D007408:Intestinal Absorption; D007558:Italy / Q000453:epidemiology; D043322:Lactase; D007785:Lactose / Q000378:metabolism*; D007787:Lactose Intolerance / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D015995:Prevalence; D012307:Risk Factors; D001616:beta-Galactosidase / Q000378:metabolism*
D043322:Lactase; D001616:beta-Galactosidase; D007785:Lactose