• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of bmjBMJ helping doctors make better decisionsSearch bmj.comLatest content
BMJ. Feb 1, 2003; 326(7383): 255–256.
PMCID: PMC140763

Cholesterol lowering drugs and risk of age related maculopathy: prospective cohort study with cumulative exposure measurement

R van Leeuwen, researcher,a J R Vingerling, ophthalmologist,b A Hofman, professor,a P T V M de Jong, professor,a and B H Ch Stricker, professora

Recently, two studies have claimed that cholesterol lowering drugs, particularly statins, protect against age related maculopathy.1,2 The end stage of this progressive retinal disorder is the commonest cause of untreatable blindness in elderly people in Western societies, and its prevalence is expected to rise with the ageing of the population. Thus, preventing this disorder would have an enormous public health impact.3 The above mentioned studies used interview data on drug use and had a low statistical power. We therefore tested the hypothesis that cholesterol lowering drugs protect against age related maculopathy in a large cohort study with cumulative exposure measured.

Participants, methods, and results

This investigation was part of the Rotterdam study, a population based cohort study of people aged 55 years and more. After the baseline phase from 1990 to 1993, two follow up examinations were performed at mean intervals of 2 and 6.5 years. Of all the subjects at risk of age related maculopathy, 4822 (83%) participated at follow up. A diagnosis of age related maculopathy was based on stereoscopic colour fundus transparencies graded according to the international classification system.4 The incidence of the disorder was defined as the development of soft distinct drusen with pigmentary irregularities, indistinct drusen, or the end stages of atrophic or neovascular age related macular degeneration.

A register of prescriptions filled by local pharmacies provided continuous data on use of cholesterol lowering drugs. These data were available for 99% of the cohort from 1 January 1991 onwards. We used Cox proportional hazards regression analysis to calculate hazard ratios, with age in days as the time axis to ensure optimal controlling for age. Cumulative exposure to drugs was represented as a time dependent covariate and was analysed both as a dichotomous and a categorical variable. The model compared each incident case of age related maculopathy with all subjects in the cohort who were alive and free of the disorder at the age when the case of maculopathy was diagnosed.5

During 26 781 person years of follow up, 457 patients used cholesterol lowering drugs for one or more days, and 419 cases of incident age related maculopathy were observed. Use of cholesterol lowering drugs at any time, defined as a binary variable, was not associated with the incidence of age related maculopathy (hazard ratio 1.0 (95% confidence interval 0.7 to 1.5)). Compared with patients who had never used cholesterol lowering drugs, cumulative exposure for less than one month, for one month to a year, or for more than a year did not have a protective effect on the risk of maculopathy (see table). Additional adjustment for body mass index, hypertension, smoking, and peripheral arterial disease (ankle:arm index <0.9) did not change the association. When we performed the same analysis with progression of age related maculopathy as the outcome variable, we obtained the same results.

Comment

Exposure to cholesterol lowering drugs did not change patients' risk of age related maculopathy. In contrast with the studies that reported a protective effect, we used a prospective design and assessed drug use by means of data registered by pharmacies. This minimised potential selection and information bias, and our data provided quantitative information for each patient's cumulative exposure to drugs. This prevented misclassification of the duration of drug use. Even though the total number of participants was high, the number of subjects using cholesterol lowering drugs who developed age related maculopathy was low, possibly leading to a type II error. With a two sided α of 0.05, we had a power of 80% to show a relative risk of 0.7 or lower. The fact that we did not find an association between cholesterol lowering drugs and age related maculopathy makes a protective effect of statins unlikely.

Table
Hazard ratios of age related maculopathy (ARM) associated with the use of cholesterol lowering drugs

Footnotes

Funding: The Rotterdam study is supported by the Netherlands Organisation for Scientific Research (NWO), the Health and Development Research Council (ZON), the Netherlands Society for the Prevention of Blindness, and the Optimix Foundation.

Competing interests: None declared.

References

1. Hall NF, Gale CR, Syddall H, Phillips DI, Martyn CN. Risk of macular degeneration in users of statins: cross sectional study. BMJ. 2001;323:375–376. [PMC free article] [PubMed]
2. McCarty CA, Mukesh BN, Guymer RH, Baird PN, Taylor HR. Cholesterol-lowering medications reduce the risk of age-related maculopathy progression. Med J Aust. 2001;175:340. [PubMed]
3. Arnold JJ, Sarks SH. Extracts from “clinical evidence”: age related macular degeneration. BMJ. 2000;321:741–744. [PMC free article] [PubMed]
4. Bird AC, Bressler NM, Bressler SB, Chisholm IH, Coscas G, Davis MD, et al. for the International ARM Epidemiological Study Group. An international classification and grading system for age-related maculopathy and age-related macular degeneration Surv Ophthalmol 1995. 39367–374.374 [PubMed]
5. In t' Veld BA, Ruitenberg A, Hofman A, Launer LJ, van Duijn CM, Stijnen T, et al. Nonsteroidal anti-inflammatory drugs and the risk of Alzheimer's disease. N Engl J Med. 2001;345:1515–1521. [PubMed]

Articles from BMJ : British Medical Journal are provided here courtesy of BMJ Group
PubReader format: click here to try

Formats:

Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...

Links

  • PubMed
    PubMed
    PubMed citations for these articles

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...