Menopausal hormone therapy, oral contraceptives and risk of chronic low back pain: the HUNT Study

Ingrid Heuch; Ivar Heuch; Knut Hagen; Kjersti Storheim; John-Anker Zwart

doi:10.1186/s12891-023-06184-5

Menopausal hormone therapy, oral contraceptives and risk of chronic low back pain: the HUNT Study

BMC Musculoskelet Disord. 2023 Jan 31;24(1):84. doi: 10.1186/s12891-023-06184-5.

Authors

Ingrid Heuch¹, Ivar Heuch², Knut Hagen^{3

4}, Kjersti Storheim^{5

6}, John-Anker Zwart^{5

7}

Affiliations

¹ Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital, Nydalen, P.O. Box 4956, N-0424, Oslo, Norway. ingrid.heuch@ous-hf.no.
² Department of Mathematics, University of Bergen, Bergen, Norway.
³ Department of Neuromedicine and Movement Science, NTNU, Norwegian University of Science and Technology, Trondheim, Norway.
⁴ Clinical Research Unit Central Norway, St. Olavs Hospital, Trondheim, Norway.
⁵ Department of Research and Innovation, Division of Clinical Neuroscience, Oslo University Hospital, Nydalen, P.O. Box 4956, N-0424, Oslo, Norway.
⁶ Faculty of Health Sciences, Oslo Metropolitan University, Oslo, Norway.
⁷ Faculty of Medicine, University of Oslo, Oslo, Norway.

Abstract

Background: There are indications that use of menopausal hormone therapy (MHT) and oral contraceptives (OC) increases the risk of low back pain (LBP), with higher oestrogen levels involved in the underlying mechanisms. The purpose of the present study was to investigate associations between use of systemic MHT or OC and risk of chronic LBP in a large population-based data set.

Methods: Data were obtained from two surveys in the Trøndelag Health Study in Norway, HUNT2 (1995-1997) and HUNT3 (2006-2008). A cross-sectional study of association between use of systemic MHT and prevalence of chronic LBP comprised 12,974 women aged 40-69 years in HUNT2, with 4007 women reporting chronic LBP. A cohort study involving MHT comprised 6007 women without chronic LBP at baseline in HUNT2, and after 11 years 1245 women reported chronic LBP at follow-up in HUNT3. The cross-sectional study of association with use of OC included 23,593 women aged 20-69 years in HUNT2, with 6085 women reporting chronic LBP. The corresponding cohort study included 10,586 women without chronic LBP at baseline in HUNT2, of whom 2084 women reported chronic LBP in HUNT3. Risk of chronic LBP was examined in both study designs in generalised linear models with adjustment for potential confounders.

Results: In the cohort study, current users of systemic MHT at baseline showed a greater risk of chronic LBP (relative risk (RR) 1.30; 95% CI: 1.14-1.49; compared with never users). The risk increased according to duration of MHT use (P for linear trend = 0.003). Known users of systemic MHT based exclusively on oestrogen experienced the highest risk (RR 1.49; 95% CI: 1.16-1.91), but an increased risk was also seen among known users of oestrogen-progestin combination MHT (RR 1.35; 95% CI: 1.16-1.57). A slight increase in risk of chronic LBP was found in the cohort study among former users of OC (RR 1.17; 95% CI: 1.06-1.30; compared with never users).

Conclusions: Long-lasting use of systemic MHT, in particular therapy based on oestrogen only, is associated with greater risk of chronic LBP. Having been a user of OC most likely entails a minor increase in risk.

Keywords: Epidemiology; HUNT; Hormone replacement therapy; Low back pain; Oestrogen; Oral contraceptives.

MeSH terms

Cohort Studies
Contraceptives, Oral
Cross-Sectional Studies
Estrogens
Female
Humans
Low Back Pain* / chemically induced
Low Back Pain* / diagnosis
Low Back Pain* / epidemiology
Menopause

Substances

Contraceptives, Oral
Estrogens