ASSESSMENT OF THE RELATION BETWEEN AGE AT MENARCHE, ANTHROP OMETRIC PARAMETERS AND INTELLIGENCE QUOTIENT IN MASHHAD, IRAN

The present study was initiated to derive an indirect method for estimating body fat mass (BFM) and to evaluate the correlation between indirect anthropometric techniques for this estimation and to examine the relation of these parameters and of IQ to age of menarche. A total of 578 adolescent girls of ten junior high schools in five educational districts of Mashhad, participated in a cross sectional study during autumn 2000. The data were gathered through questionnaires, interview, measurement of anthropometric parameters including: weight, height, BMI (Body Mass Index), TSF (Triceps Skin Fold) thickness, SSSF (Sub-Scapular Skin Fold) thickness, MUAC (Middle Upper Arm Circumference), and measurement of IQ by Raven test. We demonstrated that anthropometric parameters for estimating BFM correlated well with each other. Age at menarche did not correlate with BFM measured by anthropometric parameters when studied at the onset of menarche, but it did well correlate negatively with these indices if studied any time postmenarche, regardless of the interval between the onset of menarche and the present age (p<0.001). IQ correlated negatively to the age at menarche (p< 0.001). These findings implicate that BFM does not trigger puberty onset in healthy girls, but it does accumulate with a faster rate in the postmenarcheal period so that girls who have an earlier menarche have a higher weight and BMI and greater skinfold thickness than those who enter the menarcheal stage at a later time, and that mental development and physical growth are parallel processes, so that a slower mental development would be expected when physical growth is delayed.