INS and chronic obstructive pulmonary disease: Before human insulin, insulin glargine or other types of insulin analogs can be proven to be safe from lung carcinogenesis; the long-term use of insulin to treat diabetes should better be reserved for patients whose hyperglycemia cannot be satisfactorily treated with other anti-diabetic drugs and who are not having significant risk factors of lung cancer such as COPD as shown in the present study (Table 3).