Waistline study: Metformin for the management of insulin resistance in overweight women at midlife


What was the study about?

This study assessed the effects of metformin, a drug used to treat diabetes, on women who have put on weight but still have normal blood sugar levels.

As women reach their middle years they have a tendency to put on weight particularly around their abdominal region. The loss of oestrogen at menopause enhances this central weight gain. Abdominal fat is different to fat in the buttocks and thighs. Increased abdominal fat in women is associated with increased risk of developing high blood pressure and diabetes.

Metformin is a drug widely used to treat early type 2 diabetes. It is also the standard therapy for treating younger women with a condition known as polycystic ovarian syndrome.

This research will help to determine whether metformin might be used for prevention of diabetes, weight loss and improving cholesterol levels in middle aged women.

Who joined the study?

Overweight woman aged 35-65 years with a body mass index (BMI) between 30 and 40, and/or a waist circumference greater than 88 cm and normal fasting blood sugar (not diabetic). If you have high blood pressure or high cholesterol that is now well controlled with medication for the past six months you are able to participate. If you are on a stable dose of oestrogen and/or progestin hormone therapy you will also be eligible.

What are possible side effects of this drug?

Metformin has been used for over thirty years to treat diabetes in Australia, and is generally well tolerated.

The most common side effect from metformin is gastric upset. This may occur during the first few weeks of taking the medication but is seldom long-lasting. Taking the medication with food and starting out on a low dose helps reduce side effects.

The study involved?

Participation involved four visits to the Women's Health Research Program at the Alfred Centre [Melbourne] and one visit to a pathology collection centre. Participants were randomly allocated to be treated with either metformin or a placebo and were monitored for 26 weeks.

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