Roles of Adiposity, Lifetime Physical Activity and Serum Adiponectin in Occurrence of Breast Cancer among Malaysian Women in Klang Valley

Abstract

<b>Background:</b> Lack of physical activities throughout life is related to obesity and is a risk factor of breastcancer, however, the associations of these factors with adiponectin in the occurrence of breast cancer have notbeen well investigated. <br/><b>Objective</b>: This study investigated the relationship between adiposity, lifetime physicalactivities and serum adiponectin as breast cancer risk factors among Malaysian women in Klang Valley, Malaysia.Design: A case-control study was carried out among 70 newly diagnosed breast cancer patients and 138 controlsaged 29 to 65 years old in Klang Valley. Subjects: The inclusion criteria for both groups were not havingmenstruation for premenopausal women, no evidence of pregnancy, not lactating and no chronic diseases suchas hypertension and diabetes at the time of data collection. In addition, the cases must be pathologically newlydiagnosed with breast cancer (stage I to III) and not on any therapy for cancer, with the exception of surgery.The controls were matched with cases for age ± 5 years and menopausal status. Measurements: Subjects wereinterviewed to obtain information on socio-demography, health and reproductive history using a pretestedquestionnaire. Subjects were also asked on their engagement of physical activity since secondary school.Anthropometric parameters included height, weight, waist and hips were also measured. A total of 6 ml offasting venous blood was drawn for analysis of serum adiponectin in duplicate using Linko Adiponectin ELISAKit. Fasting blood glucose (FBG) and blood pressure were also measured. <br/><b>Results</b>: Mean body mass index(BMI) among cases and controls were not significantly different (p>0.05) at 26.1 ± 4.8 kg/m2 and 25.3 ± 4.5 kg/m2, respectively. FBG among cases (6.3 ± 1.8 mmol/L) was higher than controls (5.6 ± 1.1 mmol/L) (p<0.05).Waist hip ratio (WHR) of cases (0.85 ± 0.07) was also higher than controls (0.80 ± 0.06) (p<0.05). Abdominalobesity (WHR >0.85) increased risk of breast cancer by three folds [Adjusted OR 3.3 (95%CI 1.8-6.2)] (p<0.05).Adiponectin level was inversely related to waist circumference (r=-0.510, p=0.000), BMI (r=-0.448, p=0.000)and FBG (r=-0.290, p=0.026). Adiponectin level in cases (11.9 ± 4.8 μg/ml) were lower than controls (15.2 ± 7.3μg/ml) (p<0.05). A greater reduction of breast cancer risk was observed with the increasing level of serumadiponectin level according to percentiles (p<0.05). Subjects with mean serum adiponectin level at the highestquintile (>75th)(≥16.7 μg/ml) had 80% reduced risk of breast cancer [Adjusted OR 0.2 (0.0-0.6)](p<0.05). Ahigher percentage of cases (47%) had not engaged in any physical activity throughout life as compared tocontrols (19%)[Adjusted OR 3.7 (1.7-7.7)](p<0.001). <br/><b>Conclusions</b>: Abdominal obesity and physical inactivitythroughout life were associated with low serum adiponectin and breast cancer risk among subjects. Thus, it isessential for Malaysian women to be physically active and achieve a healthy waistline in order to increase serumadiponectin level and reduce breast cancer risk.