Risk Factors for Type 2 Diabetes Mellitus

The correct answer is Option B: 1, 3 and 4 — Family history of diabetes, Physical inactivity, and Polycystic ovary syndrome (PCOS) are all established risk factors for type 2 diabetes mellitus. Underweight is not a risk factor; in fact, being overweight/obese (not underweight) is one of the strongest risk factors for type 2 diabetes.

Analysis of Each Statement

• 1. Family history of diabetes — Correct. A first-degree relative (parent or sibling) with type 2 diabetes substantially raises an individual's risk due to shared genetic susceptibility and lifestyle factors.
• 2. Underweight — Incorrect. Type 2 diabetes is strongly associated with excess body weight and central obesity, which drive insulin resistance. Being underweight does not predispose a person to type 2 diabetes; if anything, unexplained weight loss is more typical of poorly controlled diabetes or type 1 diabetes, not a cause of it.
• 3. Physical inactivity — Correct. A sedentary lifestyle reduces skeletal muscle glucose uptake and promotes insulin resistance, making it a well-recognized modifiable risk factor for type 2 diabetes.
• 4. Polycystic ovary syndrome (PCOS) — Correct. PCOS is strongly linked to insulin resistance and hyperinsulinemia, which significantly increase the risk of developing type 2 diabetes, particularly in women who are also overweight.

Why the Other Options Are Wrong

• Option A (1, 2 and 3) — Incorrectly includes underweight (2) and omits PCOS (4), a genuine risk factor.
• Option C (1, 2 and 4) — Incorrectly includes underweight (2) and omits physical inactivity (3), a genuine risk factor.
• Option D (2, 3 and 4) — Incorrectly includes underweight (2) and omits family history (1), a genuine risk factor.

Conclusion

Only statements 1, 3, and 4 — family history, physical inactivity, and PCOS — are genuine, well-documented risk factors for type 2 diabetes mellitus, confirming Option B as the correct answer.