Is the use of statistics in medical studies entering a dangerous phase?

Here is a study that says too thin thighs may be unhealthy. The study was conducted in Denmark.

The findings held regardless of waist circumference, BMI ( body mass index), blood pressure, total cholesterol and triglyceride levels, smoking, alcohol use, education, and physical activity.

Could that also mean that all these things we care today about are irrelevant? May none of these things matter. May be they too were just statistics proved true in other parts of the world but not valid in that part of the Denmark where this study was conducted.

Have you seen the movie “Gods must be crazy”? I suppose they all got heart disease.

Did they measure the thighs of Asians in Japan, Korea and China?

What parts of the world has the lowest heart disease?