Background: Some synthetic dyes used mainly in textile industries have been associated with endocrine disruption, resulting in
infertility, among other disorders. It is unknown if occupational exposure to Vat textile dyes among premenopausal dyers alters
hormonal levels.

Objectives: We aimed at determining the probable effects of occupational exposure to Vat dyes on reproductive hormones of
female textile dyers in the follicular and luteal phases while relating this to age categories and duration of exposure.

Methods: Thirty-three premenopausal Vat textile dyers at “Itoku”, Abeokuta, Nigeria, among a population of about 80 female
dyers were age and sex-matched with 55 non-exposed (control) female participants. Using semi-structured questionnaires, socio-
demographic, occupational details and the LMP of participants were obtained. Serum samples were collected in follicular
and luteal phases and assayed for female sex hormones using Enzyme Immunoassay. Mann-Whitney U and Z- statistic were used
for comparison of the two groups. P-value < 0.05 was considered to be significant.

Results: In the follicular phase, the result showed a lower mean FSH ranking (in age category ≤20 years) and higher (p<0.05)
Estradiol ranking (in age category 31-40 years) in the exposed than the unexposed. Mean ranks of Progesterone and Estradiol in
the luteal phase (age category 31-40 years) were higher (p<0.05) in the exposed, while Estradiol (age category ≥41years) ranked
lower (p<0.05). Prolactin demonstrated a significant inverse relationship with the duration of exposure.

Conclusion: Occupational exposure to Vat dye among female dyers in Abeokuta is associated with some sex hormone disruption
which appears to be age and duration of exposure-related.

Keywords: Follicular phase; luteal phase; dye workers; sex hormone; premenopausal.