Table 1: Established breast cancer risk factors and PRL serum levels among 773 population controls in the Polish Breast Cancer Study

From: Prolactin serum levels and breast cancer: relationships with risk factors and tumour characteristics among pre- and postmenopausal women in a population-based case–control study from Poland

 Premenopausal N=230Postmenopausal N=543
 NGeometric mean PRL (ng ml–1)s.d.P-valueNGeometric mean PRL (ng ml–1)s.d.P-value
Overall geometric mean PRL23010.901.68 5437.001.74 
         
Parity
 Nulliparous1913.671.58 597.191.66 
 Parous21110.671.680.05a4846.971.610.63a
         
Age at menarche
 124911.571.69 1187.121.58 
 135211.081.74 1227.511.67 
 147610.781.52 1466.881.54 
 152110.671.81 576.601.66 
 16299.431.840.56b946.501.620.19b
         
No. of full-term births
 Nulliparous1913.671.58 597.191.66 
 17310.351.71 1767.241.69 
 210911.091.67 2256.901.55 
 3299.981.580.15b836.571.590.43b
         
Age at first full-term birth among parous women
 203512.041.59 1446.721.64 
 20–2410710.591.68 2347.121.59 
 25–296511.141.68 1237.101.58 
 30239.961.810.3b427.231.770.24b
         
Family history of breast cancer in first-degree relatives
 No22010.861.68 5066.961.76 
 Yes1011.661.770.67a377.451.490.40a
         
History of benign breast disease
 No21010.861.69 5006.931.63 
 Yes1710.931.580.78a387.661.470.22a
         
Current BMI (kg m–2)
 <2511810.991.71 1657.801.77 
 25–<306910.001.67 1897.131.59 
 304212.141.590.15b1886.221.460.0008b
         
Age at menopause among postmenopausal women
 <45    917.241.65 
 45–49    1856.821.60 
 50    2666.371.620.80b
         
Hormone therapy among postmenopausal
 Never    4226.731.62 
 Current/recent use    3110.371.67 
 Past use    297.991.44 
 Ever used oestrogen or progesterone alone    267.091.440.0006b
  1. Abbreviations: ANOVA=analysis of variance; BMI=body mass index; PRL=prolactin.
  2. aP-values from t-test.
  3. bP-values from ANOVA.