Gallbladder disease and use of transdermal versus oral hormone replacement therapy in postmenopausal women: prospective cohort study

OBJECTIVE

To determine whether transdermal compared with oral use of hormone replacement therapy reduces the risk of gallbladder disease in postmenopausal women.

DESIGN

Prospective cohort study (Million Women Study).

SETTING

Women registered with the National Health Service (NHS) in England and Scotland.

PARTICIPANTS

1,001,391 postmenopausal women (mean age 56) recruited between 1996 and 2001 from NHS breast screening centres and followed by record linkage to routinely collected NHS hospital admission data for gallbladder disease.

MAIN OUTCOME MEASURES

Adjusted relative risk and standardised incidence rates of hospital admission for gallbladder disease or cholecystectomy according to use of hormone replacement therapy.

RESULTS

During follow-up 19 889 women were admitted for gallbladder disease; 17 190 (86%) had a cholecystectomy. Compared with never users of hormone replacement therapy, current users were more likely to be admitted for gallbladder disease (relative risk 1.64, 95% confidence interval 1.58 to 1.69) but risks were substantially lower with transdermal therapy than with oral therapy (relative risk 1.17, 1.10 to 1.24 v 1.74, 1.68 to 1.80; heterogeneity P<0.001). Among women using oral therapy, equine oestrogens were associated with a slightly greater risk of gallbladder disease than estradiol (relative risk 1.79, 1.72 to 1.87 v 1.62, 1.54 to 1.70; heterogeneity P<0.001) and higher doses of oestrogen increased the risk more than lower doses: for equine oestrogens >0.625 mg, 1.91 (1.78 to 2.04) v <or=0.625 mg, 1.76 (1.68 to 1.84); heterogeneity P=0.02; estradiol >1 mg, 1.68 (1.59 to 1.77) v <or=1 mg, 1.44 (1.31 to 1.59); heterogeneity P=0.003. The risk of gallbladder disease decreased with time since stopping therapy (trend P=0.004). Results were similar taking cholecystectomy as the outcome. Standardised hospital admission rates per 100 women over five years for cholecystectomy were 1.1 in never users, 1.3 with transdermal therapy, and 2.0 with oral therapy.

CONCLUSION

Gallbladder disease is common in postmenopausal women and use of hormone replacement therapy increases the risk. Use of transdermal therapy rather than oral therapy over a five year period could avoid one cholecystectomy in every 140 users.

Relationship between body mass index and length of hospital stay for gallbladder disease

BACKGROUND

Obesity increases the risk of hospital admission for gallbladder disease but its impact on the length of hospital stay is largely unknown.

METHODS

Prospective population-based study of 1.3 million women aged 56 years on average, recruited from 1996 to 2001 in England and Scotland and followed-up through NHS hospital admission record databases for gallbladder disease (cholelithiasis, cholecystitis, cholecystectomy) over a total of 7.8 million person-years.

RESULTS

During follow-up, 24 953 women were admitted with gallbladder disease, 87% who had a cholecystectomy. After adjusting for age, socioeconomic status and other factors, women with higher BMI at recruitment to the study were more likely to be admitted and spend more days in hospital. For 1000 person-years of follow-up, women in BMI categories of 18.5-24.9, 25-29.9, 30-39.9, 40+ kg/m(2) spent, respectively, 16.5[16.0-17.0], 28.6[28.3-28.8], 44.0[43.4-44.5] and 49.4[45.7-53.0] days in hospital for gallbladder disease.

CONCLUSION

On the basis of these estimates, over a quarter of all the days in hospital for gallbladder disease in middle-aged women can be attributed to obesity.

Self-reported information on joint replacement and cholecystectomy agrees well with that in medical records

OBJECTIVES

To examine the validity of self-reported primary hip replacement, primary knee replacement, and cholecystectomy.

STUDY DESIGN AND SETTING

The data from 28,524 participants in the Million Women Study who were recruited from Scotland were linked with routinely collected Scottish hospital admission data. We compared the reporting of three operations by the study participants on a postal questionnaire with that recorded in the hospital admission database.

RESULTS

Annual incidence rates for the three operations were similar using hospital admission and self-reported data at: 2.1 (n=220) and 2.3 (n=247) per 1,000 women, respectively, for hip replacement; 1.1 per 1,000 women from both sources for knee replacement (n=118 and n=116, respectively); and 3.4 (n=357) and 3.2 (n=344) per 1,000 women, respectively, for cholecystectomy. Agreement between self-report and the hospital admission records was good for all three operations with agreements of 99.8%, 99.9%, and 99.6% for hip replacement, knee replacement, and cholecystectomy, respectively.

CONCLUSION

In middle-aged women who answered postal questionnaires, self-reporting of primary hip replacement, primary knee replacement, and cholecystectomy was found to agree well with information held in a medical record database.

Relationship of height, weight and body mass index to the risk of hip and knee replacements in middle-aged women

OBJECTIVES

To examine the effect of height, weight and body mass index (BMI) on the risk of hip and knee replacement in middle-aged women.

METHODS

In a prospective cohort study 490 532 women aged 50-69 yrs who were recruited in the UK in 1996-2001 were followed over 2.9 yrs for incident primary hip and knee replacements.

RESULTS

Height, weight and BMI were all associated with the risk of hip and knee replacement. Comparing the tallest group (>or=170 cm) with the shortest (<155 cm) the relative risks were 1.90 (95%CI 1.55-2.32) for hip replacement and 1.55 (95%CI 1.19-2.00) for knee replacement. Comparing the heaviest group (>or=75 kg) with the lightest (<60 kg) the relative risks of hip and knee replacement were 2.37 (95%CI 2.04-2.75) and 9.71 (95%CI 7.39-12.77), respectively. Comparing obese women (BMI >or= 30 kg/m(2)) to women with a BMI < 22.5 kg/m(2), the relative risks for hip and knee replacement were 2.47 (95%CI 2.11-2.89) and 10.51 (95%CI 7.85-14.08), respectively. These effects did not vary according to age, education, alcohol and tobacco consumption, or with use of hormonal therapies. Currently, an estimated 27% of hip replacements and 69% of knee replacements in middle-aged women in the UK are attributable to obesity.

CONCLUSION

In middle-aged women, the risk of having a hip or knee replacement increases with both increasing height and increasing BMI. From a clinical perspective, relatively small increases in average BMI among middle-aged women are likely to have a substantial impact on the already increasing rates of joint replacement in the UK.

Fracture incidence in relation to the pattern of use of hormone therapy in postmenopausal women

CONTEXT

Evidence is limited on the effects of different patterns of use of postmenopausal hormone therapy on fracture incidence and particularly on the effects of ceasing use.

OBJECTIVE

To investigate the effect of different patterns of hormone therapy use on fracture incidence.

DESIGN, SETTING, AND PARTICIPANTS

Prospective study of 138,737 postmenopausal women aged 50 to 69 years recruited from the UK general population in 1996-1998 (the Million Women Study) and followed up for 1.9 to 3.9 years (average, 2.8 years) for fracture incidence.

MAIN OUTCOME MEASURE

Adjusted relative risk (RR) for incident fracture (except fracture of the fingers, toes, and ribs) in hormone therapy users compared with never users at baseline.

RESULTS

A total of 5197 women (3.7%) reported 1 or more fractures, 79% resulting from falls. Current users of hormone therapy at baseline had a significantly reduced incidence of fracture (RR, 0.62; 95% confidence interval [CI], 0.58-0.66; P<.001). This protection was evident soon after hormone therapy began, and the RR decreased with increasing duration of use (P =.001). Among current users at baseline the RR of fracture did not vary significantly according to whether estrogen-only, estrogen-progestin, or other types of hormones were used (RR [95% CI], 0.64 [0.58-0.71], 0.58 [0.53-0.64], and 0.67 [0.56-0.80], respectively; P =.19), nor did it vary significantly according to estrogen dose or estrogen or progestin constituents. The RR associated with current use of hormone therapy did not vary significantly according to 11 personal characteristics of study participants, including their age at menopause, body mass index, and physical activity. Past users of hormone therapy at baseline experienced no significant protection against fractures (RR, 1.07; 95% CI, 0.99-1.15); incidence rates returned to those of never-users within about a year of ceasing use.

CONCLUSIONS

All types of hormone therapy studied confer substantial protection against fracture while they are used. This protection appears rapidly after use commences and wears off rapidly after use ceases. The older women are, the greater is their absolute reduction in fracture incidence while using hormone therapy.

Infective cause of childhood leukaemia and wartime population mixing in Orkney and Shetland, UK

In Orkney and Shetland (the UK's northernmost islands), during World War II, local people were outnumbered by servicemen stationed there in case of a northern invasion. Such rural-urban population mixing promotes contact between susceptible and infected individuals. We compared childhood leukaemia mortality in wartime and postwar cohorts of Orkney and Shetland children. Childhood leukaemia increased 3.6-fold, (p=0.001) in the wartime, but not in the postwar, cohort compared with national Scottish rates. These findings add to the evidence for infection as a cause of childhood leukaemia.

Paternal preconceptional radiation exposure in the nuclear industry and leukaemia and non-Hodgkin's lymphoma in young people in Scotland

OBJECTIVE

To determine if a relation exists between paternal exposure to relatively high levels of radiation in the Scottish nuclear industry and the risk of leukaemia and non-Hodgkin's lymphoma is subsequently conceived children.

DESIGN

Matched case-control study with three controls for each case.

SETTING

The whole of Scotland.

SUBJECTS

The fathers of 1024 children with leukaemia and 237 children with non-Hodgkin's lymphoma diagnosed in Scotland below the age of 25 among those born in Scotland since nuclear operations began (in 1958) and the fathers of 3783 randomly chosen controls. The fathers of 80 children with leukaemia and 16 with non-Hodgkin's lymphoma in north Cumbria were also covered since some workers at one Scottish nuclear site live over the border in that area. Details of all fathers were then matched against records of the nuclear industry.

MAIN OUTCOME MEASURES

Paternal preconceptional radiation exposures, particularly relatively high levels, both lifetime and in the six and three months before conception.

RESULTS

No significant excess was observed in any subgroup and there was no significant trend: fathers of three controls but no cases were exposed to lifetime preconceptional levels of 100 mSv or greater (Fisher's exact p value 0.84). In the six months before conception, fathers of two cases and three controls received 10 mSv or more, odds ratio 2.3 (95% confidence interval 0.31 to 17.24). In the three months before conception the fathers of one case and two controls received 5 mSv or more, odds ratio 1.7 (0.10 to 30.76). The results for leukaemia and non-Hodgkin's lymphoma combined were similar.

CONCLUSIONS

No significant excess of leukaemia or of leukaemia and non-Hodgkin's lymphoma was found at any radiation level in any preconceptional period.

Rural population mixing and childhood leukaemia: effects of the North Sea oil industry in Scotland, including the area near Dounreay nuclear site

OBJECTIVE

To determine if any excess of childhood leukaemia and non-Hodgkin's lymphoma was associated with certain striking examples of population mixing in rural Scotland produced by the North Sea oil industry.

DESIGN

Details were traced for over 30,000 workers involved in the construction of the large oil terminals in the Shetland and Orkney islands in northern Scotland or employed offshore. Home addresses of the 17,160 Scottish residents were postcoded, integrated with census data, and then classified as urban or rural. Rural postcode sectors, ranked by proportion of oil workers, were grouped into three categories with similar numbers of children but contrasting densities of oil workers. The incidence of leukaemia and non-Hodgkin's lymphoma was examined in these rural (and also in urban) categories in the periods 1974-8, 1979-83 and 1984-8.

SETTING

Scotland.

SUBJECTS

Young people below age 25.

RESULTS

A significant excess of leukaemia and non-Hodgkin's lymphoma was found in 1979-83 in the group of rural home areas with the largest proportion of oil workers, following closely on large increases in the workforce. The area near the Dounreay nuclear installation, where an excess of leukaemia is already well known, was within the rural high oil category.

CONCLUSION

The findings support the infection hypothesis that population mixing can increase the incidence of childhood leukaemia in rural areas. They also suggest that the recent excess in the Dounreay-Thurso area is due to population mixing linked to the oil industry, promoted by certain unusual local demographic factors.