Much of this work has focused on enteroviruses, with some studies finding slight associations with type 1 diabetes, and others finding none. Large human studies have searched for, but not yet found an association between type 1 diabetes and various other viral infections, including infections of the mother during pregnancy. Conversely, some have postulated that reduced exposure to pathogens in the developed world  increases the risk of autoimmune diseases, often called the hygiene hypothesis. Various studies of hygiene-related factors – including household crowding, daycare attendance, population density, childhood vaccinations, antihelminth medication, and antibiotic usage during early life or pregnancy – show no association with type 1 diabetes. Genetics
Type 1 diabetes is partially caused by genetics, and family members of type 1 diabetics have a higher risk of developing the disease themselves. In the general population, the risk of developing type 1 diabetes is around 1 in 250. For someone whose parent has type 1 diabetes, the risk rises to 1–9%. If a sibling has type 1 diabetes, the risk is 6–7%. If someones identical twin has type 1 diabetes, they have a 30–70% risk of developing it themselves.About half of the diseases heritability is due to variations in three HLA class II genes involved in antigen presentation: HLA-DRB1, HLA-DQA1, and HLA-DQB1. The variation patterns associated with increased risk of type 1 diabetes are called HLA-DR3 and HLA-DR4-HLA-DQ8, and are common in people of European descent. A pattern associated with reduced risk of type 1 diabetes is called HLA-DR15-HLA-DQ6.
Treatment and prognosis
Typically, tissue plasminogen activator may be administered within 3 to 4.5 hours of stroke onset if the patient is without contraindications (i.e. a bleeding diathesis such as recent major surgery or cancer with brain metastases). High dose aspirin can be given within 48 hours. For long term prevention of recurrence, medical regimens are typically aimed towards correcting the underlying risk factors for lacunar infarcts such as hypertension, diabetes mellitus and cigarette smoking. Anticoagulants such as heparin and warfarin have shown no benefit over aspirin with regards to five-year survival.Patients who have lacunar strokes have a greater chance of surviving beyond thirty days (96%) than those with other types of stroke (85%), and better survival beyond a year (87% versus 65-70%). Between 70% and 80% are functionally independent at 1 year, compared with fewer than 50% otherwise.Occupational therapy and physical therapy interventions are used in the rehabilitation of lacunar stroke. A physiotherapy program will improve joint range of motion of the paretic limb using passive range of motion exercises. When increases in activity are tolerated, and stability improvements are made, patients will progress from rolling to side-lying, to standing (with progressions to prone, quadruped, bridging, long-sitting and kneeling for example) and learn to transfer safely (from their bed to a chair or from a wheel chair to a car for example). Assistance and ambulation aids are used as required as the patient begins walking and lessened as function increases.