Table 3: Selected characteristics of studies in premenopausal women included in the paper.

Authors, years, and countryStudy designPopulationCases/controls or P-yearsType of exposureRange of exposureRR (95% CI)Variables of adjustment or comments

Weiderpass et al., 2004
Norway-Sweden [53]
CohortCaucasian733/99,717BMI
BMI at age 18
Body shape at age 7
>30 versus <20  
≥25 versus 20–24.9  
Fat/very fat versus average
0.62 (0.40–0.97)   
0.74 (0.59–0.91)   
0.69 (0.50–0.93)
Age at enrolment, parity, age at FFT pregnancy, OC, age at menarche, FHBC, total duration of breast feeding, and country
Lahmann et al., 2004
Germany [23]
CohortCaucasian474/73,542BMI
WHR
≥28.8 versus <21.5
>0.846 versus <0.736
0.82 (0.59–1.14)
1.05 (0.74–1.50)
Study center, age, educational attainment, smoking, alcohol, parity, age at first pregnancy, age at menarche, and current pill use
Baer et al., 2005
United States [54]
CohortCaucasian1,318/109,267Increase body fatnessAge, time period, birth weight, height,
recent alcohol consumption, parity, age
at first birth, OC, history of benign breast disease, and first degree of FHBC
 From age 5 to 10≥2 levels versus no change0.77 (0.61–0.98)
 From age 5 to 20≥2 levels versus no change0.77 (0.65–0.91)
 From age 10 to 20≥2 levels versus no change0.82 (0.67–0.99)
Tehard and Clavel-Chapelon, 2006
France [28]
Cohort Caucasian275/20,068BMI
WHR
>30 versus <18.5
≥0.82 versus 0.74
0.26 (0.06–1.00)   
0.60 (0.39–0.91)
FHBC, age at menarche, age at FFTP, parity, history of benign breast disease, alcohol consumption, education, marital status, and physical activity
Baer et al., 2010
United States [45]
CohortCaucasian2,188/188,860Body fatness
 Childhood 5–10 Y
 Adolescent 10–20 Y
  
0.2 unit increase
0.1 unit increase
  
0.91 (0.87–0.94)
0.88 (0.87–0.94)
Age, time period, parity, age at first birth, FHBC, personal history of benign breast disease, height, alcohol intake, OC, and birth weight
Harris et al., 2011
United States [31]
CohortCaucasian620/45,799WHR ER−≥0.84 versus <0.731.95 (1.10–3.46)Age, height, history of benign breast disease, FHBC, age at menarche, age at FFTP, parity, OC, alcohol, and physical activity
Kuriyama et al., 2005
Japan [46]
Cohort Asian33/5,214 BMI≥29.9 versus <25
≥30 versus <25
0.84 (0.24–2.88)   
2.67 (1.03–6.92)
Age, smoking, alcohol, consumption of meat, fish, fruits, green or yellow consumption of bean-paste soup, type of health, parity, age at menarche, and age at FFT pregnancy
Iwasaki et al., 2007Japan [47] CohortAsian441/55,537BMI>30 versus <19 1.47 (0.53–3.47)Age, area, number of births, age at first birth, and height
Wu et al., 2006
Taiwan [55]
CohortAsian104/11,889BMI
WHR
>26.2 versus 21.6
<0.85 versus <0.77
1.90 (1.00–3.40)
0.60 (0.30–1.20)
Age at enrollment, height, weight
Kawai et al., 2010  Japan [22]CohortAsian108/10,106BMI≥25 versus <202.54 (1.16–5.55)Age, education level, smoking, alcohol, time spent walking, which are known or suspected risk factors for BC. Menstrual and reproductive factors, HRT, and FHBC
Palmer et al., 2007
United States [35]
CohortAfrican-American496/59,000BMI at age 18 years Current BMI
WHR
≥25 versus <20
≥37 versus <25
≥0.87 versus <0.71
0.68 (0.46–0.87)   
0.72 (0.54–0.96)   
1.16 (0.85–1.59)
Age, age at menarche, parity, age at first birth, FHBC
Enger et al., 2000
United States [56]
Case-controlCaucasian701/714BMI Age at reference year, socioeconomic status, age at menarche, age at FFT, number of full-term pregnancies, months of breastfeeding
 ER+PR+ >32.4 versus <17.36 1.11 (0.7–1.77)
 ER+PR−>32.4 versus <17.36 0.92 (0.34–2.47)
 ER−PR−>32.4 versus <17.36 1.07 (0.56–1.68)
Friedenreich et al., 2002
Canada [48]
Case-controlCaucasian462/475BMI
WHR
≥29.2 versus <23.1
≥0.81 versus <0.72
0.69 (0.47–1.02)
1.22 (0.84–1.79)
Age, total caloric intake, physical activity, educational level, HRT, diagnosed with benign BC, FHBC, alcohol, and smoking
Magnusson and Roddam, 2005
United kingdom [57]
Case-controlCaucasian1560/1548Body fatness at 10 Y
Change between 10 and diagnosis
Plump versus thin
Plump/overweight versus thin/thin
0.83 (0.69–0.99)   
0.75 (0.56–1.01)
Age and recruitment, region, parity, age at first birth, height, OC, and alcohol
Berstad et al., 2010 United States [30]Case-controlCaucasian2,097/2,035BMI at 18 years
Recent BMI
≥25 versus <20
≥35 versus <25
0.76 (0.63–0.90)   
0.81 (0.61–1.06)
Age, race, education, study site, family history, parity, age at menopause, and HT use
Wenten et al., 2002
United States [50]
Case-controlCaucasian
Hispanic
687/820BMI Age; FHBC; total MET-hours; parity; OC; breastfeeding; and age at first live birth
 Caucasian≥30 versus <220.71 (0.19–2.63)
 Hispanic≥30 versus <221.64 (0.52–5.11)
Slattery et al., 2007
United States [36]
Case-controlCaucasian
Hispanic
2,325/2,525Current BMIAge, height, physical activity, energy intake, parity, alcohol consumption, age at first pregnancy, and center
 Caucasian>30 versus <250.82 (0.58–1.17)
 Hispanic>30 versus <250.96 (0.63–1.46)
BMI at 30 years
 Caucasian>30 versus <250.91 (0.52–1.60)
 Hispanic>30 versus <250.46 (0.25–0.84)
John et al., 2011  
United States [58]
Case-controlCaucasian
African-American
Hispanic
672/808BMI all
 African-American  
 Caucasian  
 Hispanic  
WHR
 African-American  
 Caucasian  
 Hispanic
>30 versus <25  
>30 versus <25  
>30 versus <25  
>30 versus <25  
>0.85 versus ≤0.77  
>0.85 versus ≤0.77  
>0.85 versus ≤0.77  
>0.85 versus ≤0.77
0.60 (0.45–0.79)   
0.65 (0.35–1.23)   
0.60 (0.28–1.30)   
0.52 (0.35–0.77)   
0.78 (0.56–1.08)   
0.82 (0.39–1.74)   
1.35 (0.47–3.86)   
0.71 (0.46–1.11)
Age, country of birth, education level, FHBC biopsy-confirmed history of benign breast disease, age at menarche, parity, breastfeeding, alcohol, physical activity, daily caloric intake, and height. Analyses of all women combined were also adjusted for race/ethnicity
Ng et al., 1997
Singapore [33]
Case-control Asian74/297WHR>0.86 versus <0.757.81 (2.8–21.9)Age, menopausal status, age at menarche, parity, number of birth, age FFT birth, HR, OC, breast feeding, smoking, height, weight, BMI
Chow et al., 2005 China [20]Case-controlAsian198/353BMI27–31 versus <19 1.32 (0.39–4.43) Age, number of pregnancies, FHBC, income, smoking, alcohol, use of OC, education
Sangaramoorthy et al., 2011
United States [59]
Case-controlHispanic210/265Weight at age 10
Weight at age 15 Weight at age 20
Heavier versus lighter
Heavier versus lighter
Heavier versus lighter
0.63 (0.33–1.20)
0.31 (0.16–0.61)   
0.44 (0.24–0.84)
Age, country of birth, education, FHBC, prior biopsy-confirmed history of benign breast disease, parity, lifetime, breastfeeding, age at FFT, OC, adult height, alcohol consumption, and average caloric intake
Huang et al., 1999  
United States [38]
Case-controlCaucasian
African-American
436/354BMI all
 ER+PR+
 ER−PR−
WHR all
 ER+PR+
 ER−PR−
>31 versus <31
>31 versus <31
>31 versus <31
>0.8 versus ≤0.8
>0.8 versus ≤0.8
>0.8 versus ≤0.8
1.00 (0.70–1.30)
1.10 (0.70–1.70)
0.70 (0.40–1.20)
1.40 (1.10–1.70)   
1.40 (1.00–1.90)   
1.40 (0.90–2.00)
Age at menarche, nulliparity, breastfeeding, abortion or miscarriage, BMI, WHR, oral contraceptive, HRT, FHBC, smoking, alcohol, education, medical radiation to the chest
Hall et al., 2000
United States [40]
Case-controlCaucasian
African-American
390/319BMI Age, age at menarche, parity/age at FFT pregnancy, lactation, education
 Black14.6–24.6 versus 30.1–58.20.89 (0.38–2.07)
 White14.6–24.6 versus 30.1–58.20.46 (0.26–0.80)
WHR
 Black0.6–0.77 versus 0.86–1.342.50 (1.10–5.67)
 White0.6–0.77 versus 0.86–1.342.44 (1.17–5.09)
Adebamowo et al., 2003  
Nigeria [49]
Case-controlAfrican234/273 BMI≥30 versus <201.21 (0.56–2.60)Age, age at menarche, age at first pregnancy, height
Ogundiran et al., 2010
Nigeria [34]
Case-controlAfrican707/820BMI31.2 versus <19.5
≥28 versus <21
0.70 (0.50–0.98)   
0.76 (0.48–1.21)
Age, ethnicity, education, age at menarche, number of live births, age at first live birth, duration of breastfeeding, menopausal status, FHBC, benign BC, OC, and alcohol
Wu et al., 2007  
Asian [39]
Case-controlAsian1,277/1,160BMI
WHR
>24.60 versus ≤20.43
>0.84 versus ≤0.76
0.67 (0.46–0.98)   
1.20 (0.82–1.77)
Age, Asian ethnicity, duration of residence in the US, education, age at menarche, number of live births, menopausal status, intake of tea and soy during adolescence and adult life, and physical activity
Ma et al., 2006
United States [60]
Case-controlAsian1,725/440BMI ≥35 versus <250.61 (0.38–0.99)Race, age, education, first-degree FHBC, age at menarche, gravity, number of full-term pregnancy, BMI 1 year before reference date, OC
Mathew et al., 2008 India [24]Case-controlAsian898/1,182BMI25–29.9 versus <25
>30 versus <25
1.33 (1.50–1.62)   
1.56 (1.03–2.35)
Age, center, religion, marital status, education, socioeconomic status, residence status, parity, age at 1st childbirth, breast feeding, and physical activity
Connolly et al., 2002
Canada [37]
Meta-analysisAll19 studiesWHR0.1 unit increase1.79 (1.22–2.62)A meta-analysis was done to summarize literature on WHR and breast cancer risk published from January 1966 to August 2002
Harvie et al., 2003
United kingdom [32]
All 8 studies:
5 cohort and
3 case-control
WHRLifestyles and reproductive factors
(confounders that were found to be
significant in proportional hazard regression analysis)
Meta-analysis Cohort studies>0.80 versus <0.751.59 (1.14–2.22)
 Case-control studies >0.80 versus <0.752.70 (1.52–4.76)
Suzuki et al., 2009
Sweden [27]
Meta-analysis All31 studies:
9 cohort and
22 case-control
BMI ER+PR+5 units increase0.90 (0.82–0.99)Meta-analysis of cohort and case-control studies (from 1970 to 2007) between body weight, and the incidence of BC defined by ER/PR status
Van Den Brandt et al., 2000
United States [29]
Meta-analysisCaucasian7 cohort studies BMI>31 versus <210.54 (0.34–0.85)OC use, history of benign BC, FHBC, smoking status, education, fat intake, fiber intake, energy intake, and alcohol intake
Renehan et al., 2008
United States [25]
Meta-analysisCaucasian
Asian
20 studies
79,30/2, 559,829
BMI (all)5 units increase0.92 (0.88–0.97)Cohort and case-control studies published from 1966 to November 2007 were included in the analysis. The dose response meta-analysis was adjusted by geographic region and cancer site
 North American5 units increase0.91 (0.85–0.98)
 European and
 Australian
5 units increase0.89 (0.84–0.94)
 Asia-Pacific5 units increase1.16 (1.01–1.32)

BMI: measurement of body mass index (in kg/m2); WHR: waist-hip ratio; ER: Estrogen receptor; PR: progesterone receptor; BC: breast cancer; HRT: hormonal replacement therapy; OC: oral contraceptives; FFT: age at first full term pregnancy; FHBC: family history of breast cancer; Y: years.
Bold: statistically significant.