Table 2 Reproductive factors and risk of melanoma among women in the NIH-AARP Diet and Health Study

From: Reproductive factors, exogenous hormone use and incidence of melanoma among women in the United States

Factor

No. of woman-yearsa

No. of casesa

HRb (95% CI)

P for trendc

Age at menarched

    

 ≥15 years

206,674

87

Reference

 

  13–14 years

960,120

423

1.03 (0.81–1.29)

 

  11–12 years

965,658

461

1.14 (0.91–1.44)

 

  ≤10 years

151,591

75

1.25 (0.92–1.71)

0.04

No. of live births

    

  Nulliparous

339,783

167

1.24 (1.00–1.53)

 

  1–2

826,809

357

Reference

 

  ≥3

1,115,914

524

1.08 (0.95–1.24)

0.75

Age at first live birth among parous women

    

  <20 years

375,890

133

Reference

 

  20–29 years

1,431,289

689

1.22 (1.01–1.48)

 

  ≥30 years

129,880

57

1.08 (0.78–1.48)

0.25

Menopausal reason

    

  Natural menopause

1,277,438

569

Reference

 

  Surgical menopause

1,005,338

473

1.07 (0.93–1.21)

 

Age at menopausee

    

  <45 years

771,682

314

Reference

 

  45–49 years

577,132

263

1.19 (1.00–1.42)

 

  ≥50 years

930,360

467

1.34 (1.13–1.59)

0.001

Age at natural menopause

    

  <40 years

26,596

6

0.66 (0.28–1.55)

 

  40–44 years

118,110

42

Reference

 

  45–49 years

354,837

142

1.11 (0.79–1.57)

 

  ≥50 years

773,958

376

1.30 (0.94–1.79)

0.01

Age at surgical menopause

    

  <40 years

377,003

143

0.79 (0.62–1.01)

 

  40–44 years

248,521

122

Reference

 

  45–49 years

220,837

120

1.09 (0.85–1.40)

 

  ≥50 years

153,451

87

1.11 (0.85–1.47)

0.005

Ovary status, among surgical menopause

    

  Both removed

530,124

262

Reference

 

  Both intact

382,470

174

0.92 (0.76–1.15)

 
  1. CI confidence interval, HR hazard ratio, NIH National Institutes of Health
  2. aIncludes 167,503 women and 2,299,578 total woman-years, but numbers may be inconsistent because of missing values
  3. bAdjusted for age, ambient ultraviolet radiation quartile (coded continuously 1–4), education (less than high school, high school, some college, college or graduate school, body mass index (>18.5–<25, 25–<30, 30–<60 kg/m2), smoking status (never, former, current), marriage (married, widowed, divorced/separated, never married), family history of cancer (no, yes), colonoscopy or sigmoidoscopy (no, yes), menopausal hormone therapy (no, yes)
  4. cTrend tests were conducted by modeling ordinal categories as continuous
  5. dAdjusted for factors mentioned in Table footnote b and menopausal age (<45, 45–49, 50+ years)
  6. eAdjusted for factors mentioned in Table footnote b and menopausal reason (natural menopause, surgical menopause)
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