Person:

Schaumberg, Debra A.

Vitamin D has been shown to have anti-angiogenic properties and to play a protective role in several types of cancer, including breast, prostate and cutaneous melanoma. Similarly, vitamin D levels have been shown to be protective for risk of a number of conditions, including cardiovascular disease and chronic kidney disease, as well as numerous autoimmune disorders such as multiple sclerosis, inflammatory bowel diseases and type 1 diabetes mellitus. A study performed by Parekh et al. was the first to suggest a role for vitamin D in age-related macular degeneration (AMD) and showed a correlation between reduced serum vitamin D levels and risk for early AMD. Based on this study and the protective role of vitamin D in diseases with similar pathophysiology to AMD, we examined the role of vitamin D in a family-based cohort of 481 sibling pairs. Using extremely phenotypically discordant sibling pairs, initially we evaluated the association of neovascular AMD and vitamin D/sunlight-related epidemiological factors. After controlling for established AMD risk factors, including polymorphisms of the genes encoding complement factor H (CFH) and age-related maculopathy susceptibility 2/HtrA serine peptidase (ARMS2/HTRA1), and smoking history, we found that ultraviolet irradiance was protective for the development of neovascular AMD (p = 0.001). Although evaluation of serum vitamin D levels (25-hydroxyvitamin D [25(OH)D]) was higher in unaffected individuals than in their affected siblings, this finding did not reach statistical significance. Based on the relationship between ultraviolet irradiance and vitamin D production, we employed a candidate gene approach for evaluating common variation in key vitamin D pathway genes (the genes encoding the vitamin D receptor [VDR]; cytochrome P450, family 27, subfamily B, polypeptide 1 [CYP27B1]; cytochrome P450, family 24, subfamily A, polypeptide 1 [CYP24A1]; and CYP27A1) in this same family-based cohort. Initial findings were then validated and replicated in the extended family cohort, an unrelated case-control cohort from central Greece and a prospective nested case-control population from the Nurse's Health Study and Health Professionals Follow-Up Studies, which included patients with all subtypes of AMD for a total of 2,528 individuals. Single point variants in CYP24A1 (the gene encoding the catabolising enzyme of the vitamin D pathway) were demonstrated to influence AMD risk after controlling for smoking history, sex and age in all populations, both separately and, more importantly, in a meta-analysis. This is the first report demonstrating a genetic association between vitamin D metabolism and AMD risk. These findings were also supplemented with expression data from human donor eyes and human retinal cell lines. These data not only extend previous biological studies in the AMD field, but further emphasise common antecedents between several disorders with an inflammatory/immunogenic component such as cardiovascular disease, cancer and AMD.

Advanced glycation end products (AGEs) have been implicated in the pathogenesis of sarcopenia. Our aim was to characterize the relationship between serum carboxymethyl-lysine (CML), a major circulating AGE, and incident severe walking disability (inability to walk or walking speed (<0.4) m/sec) over 30 months of followup in 394 moderately to severely disabled women, (\ge 65) years, living in the community in Baltimore, Maryland (the Women's Health and Aging Study I). During followup, 154 (26.4%) women developed severe walking disability, and 23 women died. Women in the highest quartile of serum CML had increased risk of developing of severe walking disability in a multivariate Cox proportional hazards model, adjusting for age and other potential confounders. Women with elevated serum CML are at an increased risk of developing severe walking disability. AGEs are a potentially modifiable risk factor. Further work is needed to establish a causal relationship between AGEs and walking disability.

Purpose Dry eye disease affects women twice as often as men, but there is little information on whether dry eye treatments, treatment satisfaction, or the impact of dry eye disease on patients’ lives and vision might differ by sex. Design: Questionnaire survey of 4000 participants in the Women’s Health Study and the Physicians’ Health Studies I and II with a prior report of a diagnosis of DED. Methods: Among participants who re-confirmed a diagnosis of dry eye disease, we assessed symptoms, treatments, patient satisfaction and impact of dry eye disease, and analyzed differences between men and women using regression models. Results: The final study population consisted of 1,518 women (mean age 70.7 years) and 581 men (mean age 76.7 years), with a mean reported duration of dry eye disease of 10.5 years and 10.1 years, respectively. The frequency and severity of dry eye disease symptoms were higher among women (each P<0.0001), and women reported a greater impact on everyday activities (P<0.0001). Women were more likely to use artificial tears (P<0.0001) use them more often (P<0.0001), and to use Restasis® (P<0.0001), omega-3 fatty acids (P=0.0006), and have punctal occlusion (P=0.005). Women spent more money per month on dry eye treatments (P<0.0001), but reported greater dissatisfaction with treatment side effects (P=0.001), and the amount of time before treatments started working (P=0.03). Conclusions: These data show that dry eye disease is generally experienced as being more severe among women, having a greater impact on their self-assessed well-being.

In developing countries, household air pollution (HAP) resulting from the inefficient burning of coal and biomass (wood, charcoal, animal dung and crop residues) for cooking and heating has been linked to a number of negative health outcomes, mostly notably respiratory diseases and cancers. While ocular irritation has been associated with HAP, there are sparse data on adverse ocular outcomes that may result from acute and chronic exposures. We consider that there is suggestive evidence, and biological plausibility, to hypothesize that HAP is associated with some of the major blinding, and painful, eye conditions seen worldwide. Further research on this environmental risk factor for eye diseases is warranted.

Genetic case-control association studies often include data on clinical covariates, such as body mass index (BMI), smoking status, or age, that may modify the underlying genetic risk of case or control samples. For example, in type 2 diabetes, odds ratios for established variants estimated from low–BMI cases are larger than those estimated from high–BMI cases. An unanswered question is how to use this information to maximize statistical power in case-control studies that ascertain individuals on the basis of phenotype (case-control ascertainment) or phenotype and clinical covariates (case-control-covariate ascertainment). While current approaches improve power in studies with random ascertainment, they often lose power under case-control ascertainment and fail to capture available power increases under case-control-covariate ascertainment. We show that an informed conditioning approach, based on the liability threshold model with parameters informed by external epidemiological information, fully accounts for disease prevalence and non-random ascertainment of phenotype as well as covariates and provides a substantial increase in power while maintaining a properly controlled false-positive rate. Our method outperforms standard case-control association tests with or without covariates, tests of gene x covariate interaction, and previously proposed tests for dealing with covariates in ascertained data, with especially large improvements in the case of case-control-covariate ascertainment. We investigate empirical case-control studies of type 2 diabetes, prostate cancer, lung cancer, breast cancer, rheumatoid arthritis, age-related macular degeneration, and end-stage kidney disease over a total of 89,726 samples. In these datasets, informed conditioning outperforms logistic regression for 115 of the 157 known associated variants investigated (P-value = 1×(10^{−9})). The improvement varied across diseases with a 16% median increase in χ2 test statistics and a commensurate increase in power. This suggests that applying our method to existing and future association studies of these diseases may identify novel disease loci.

Objective To estimate the prevalence and risk factors for dry eye disease (DED) among US men.

Methods Cross-sectional prevalence survey among male participants 50 years and older in the Physicians' Health Studies I (N = 18 596) and II (N = 6848). We defined DED as the presence of clinically diagnosed dry eye or severe symptoms (both dryness and irritation constantly or often). We calculated the age-standardized prevalence of DED adjusted to the age distribution of US men in 2004 and projected estimates forward to 2030. We compared DED prevalence with a similar cohort of women and examined associations with possible risk factors.

Results The prevalence of DED increased with age, from 3.90% among men aged 50 to 54 years to 7.67% among men 80 years and older (Pfor trend <.001). High blood pressure (odds ratio, 1.28; 95% confidence interval, 1.12-1.45) and benign prostatic hyperplasia (odds ratio, 1.26; 95% confidence interval, 1.09-1.44) were associated with a higher risk of DED. Use of antidepressants, antihypertensives, and medications to treat benign prostatic hyperplasia were also associated with increased risk of DED. The age-standardized prevalence of DED was 4.34%, or 1.68 million men 50 years and older, and is expected to affect more than 2.79 million US men by 2030.

Conclusions Dry eye disease is prevalent and increases with age, hypertension, benign prostatic hyperplasia, and antidepressant use.

Context Postmenopausal hormone replacement therapy (HRT) use is common in the United States. Some research suggests that estrogen may have detrimental effects on the tear film and could influence the development of dry eye syndrome, but few data are available on this relationship.

Objective To determine the relationship of HRT and dry eye syndrome.

Design, Setting, and Participants The Women's Health Study, a large cohort study in which 25 665 postmenopausal women provided information about use of HRT at baseline (1992), 12, and 36 months and dry eye syndrome at 48 months.

Main Outcome Measures (1) Clinically diagnosed dry eye syndrome, as reported by participants; (2) severe symptoms (both ocular dryness and irritation either constantly or often); and (3) either clinically diagnosed dry eye syndrome or severe symptoms, compared between women who used HRT vs those who did not.

Results For the combined end point of either clinically diagnosed dry eye syndrome or severe symptoms, the multivariable-adjusted odds ratios were 1.69 (95% confidence interval [CI], 1.49-1.91) for estrogen use alone and 1.29 (95% CI, 1.13-1.48) for estrogen plus progesterone/progestin use compared with no HRT use. Each 3-year increase in the duration of HRT use was associated with a significant 15% (95% CI, 11%-19%) elevation in risk of clinically diagnosed dry eye syndrome or severe symptoms. Results were similar for the combined end point of clinically diagnosed dry eye syndrome and severe symptoms.

Conclusions These data suggest that women who use HRT, particularly estrogen alone, are at increased risk of dry eye syndrome. Physicians caring for women who are taking or considering HRT should be apprised of this potential complication.

Context Low-level lead exposure may increase the risk for a number of chronic age-related diseases. Several studies have documented the presence of lead in lenses with cataract. The intrusion of lead into the lens may alter lens redox status and cause protein conformational changes that decrease lens transparency.

Objective To determine the relationship of cumulative lead exposure with the development of cataract.

Design, Setting, and Participants Tibial (cortical) and patellar (trabecular) bone lead levels were measured by K x-ray fluorescence between 1991 and 1999 in a subset of participants in the Normative Aging Study (NAS), a Boston-based longitudinal study of aging in men. Among the first 795 NAS participants to have bone lead levels measured, we reviewed eye examination data (collected routinely every 3-5 years) for the period after the bone lead measurements were taken. We limited the population to men aged 60 years and older who had sufficient eye examination information available (n = 642). Blood lead levels were also measured.

Main Outcome Measures Cataract assessment was done while masked to the lead level results. A participant was considered to have cataract if there was documentation for either eye of cataract surgery or a cataract graded clinically as 3+ or higher on a 4-point scale. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated as estimates of the magnitude and significance of the relationship of lead exposure with cataract, in logistic regression models.

Results The mean age of the study participants was 69 years and cataract was identified in 122 men. The age-adjusted OR (95% CI) for cataract for men in the highest vs lowest quintile of tibia lead level was 2.68 (1.31-5.50). Further adjustment for pack-years of cigarette smoking, diabetes, blood lead levels, and intake of vitamin C, vitamin E, and carotenoids resulted in an OR of 3.19 (95% CI, 1.48-6.90). For patella lead level, there was an increased risk of cataract in the highest vs lowest quintile (OR, 1.88; 95% CI, 0.88-4.02), but the trend was not significant (P = .16). Blood lead levels, more indicative of short-term exposure levels, were not significantly associated with cataract (OR, 0.89; 95% CI, 0.46-1.72; P = .73).

Conclusions These epidemiological data suggest that accumulated lead exposure, such as that commonly experienced by adults in the United States, may be an important unrecognized risk factor for cataract. This research suggests that reduction of lead exposure could help decrease the global burden of cataract.

Background: Dry eye syndrome (DES) is a prevalent ocular condition, but information on risk or protective factors is lacking.

Objective: We aimed to determine the association between dietary intake of n-3 and n-6 fatty acids and their ratio and the presence of DES.

Design: Of the 39,876 female health professionals in the Women's Health Study (WHS), we studied cross-sectionally 32,470 women aged 45 to 84 years who provided information on diet and DES. We assessed intake of fatty acids by a validated food frequency questionnaire, and DES using self-reports of clinically diagnosed cases. Of the sample, 1546 (4.7%) subjects reported a clinical diagnosis of DES. We used logistic regression models to estimate the odds ratios (OR) and 95% confidence intervals (CI) to describe the relationships of fatty acid intake with DES. We analyzed the association between consumption of fish and DES in a similar way. Results: After adjusting for demographic factors, hormone therapy, and total fat intake, the OR (CI) for the highest versus lowest fifth of n-3 fatty acids was 0.83 (0.70-0.98), P[trend]=0.05. A higher ratio of n-6/n-3 fatty acid consumption was associated with significantly increased risk of DES, OR (CI) =2.51 (1.13-5.58) for >15/1 versus <4/1 (P[trend]=0.01). In addition, tuna consumption was inversely associated with DES (OR=0.81, CI=0.66-0.99 for 2-4 113 g (4 oz) servings/week, and OR=0.32, CI=0.13-0.79 for 5-6 servings/week versus ≤1 servings/week; P[trend]=0.005).

Conclusion: These results suggest that a higher dietary intake of n-3 fatty acids is associated with a decreased presence of DES in women. These findings are consistent with anecdotal clinical observations and postulated biological mechanisms.

Purpose

To evaluate the impact of dry eye syndrome (DES) on vision-associated quality of life.

Design

Cross-sectional study.

Methods

We identified 450 participants in the Women’s Health Study (WHS) and 240 participants in the Physicians’ Health Study (PHS) and sent a supplementary questionnaire asking how much their everyday activities were limited by symptoms of dry eye and to what degree problems with their eyes limited them in reading, driving, working at the computer, their professional activity, and watching TV. By design, one-third of study subjects had clinically diagnosed DES or severe symptoms and two-thirds did not. We used logistic regression to examine relationships of DES with reported problems with everyday activities in each cohort and pooled estimates using meta-analysis methods.

Results

Of the participants invited, 85% completed the supplementary questionnaire, including 135 WHS and 55 PHS participants with DES, and 250 WHS and 149 PHS participants without DES. Controlling for age, diabetes, hypertension and other factors, those with DES were more likely to report problems with reading (OR=3.64, 95% CI 2.45–5.40, P< 0.0001); carrying out professional work (OR=3.49, 95% CI 1.72–7.09, P= 0.001); using a computer (OR=3.37, 95% CI 2.11–5.38, P< 0.0001); TV watching (OR=2.84, 95% CI 1.05–7.74, P=0.04); driving during the day (OR=2.80, 95% CI 1.58–4.96, P< 0.0001); and driving at night (OR=2.20, 95% CI 1.48–3.28, P<0.0001).

Conclusions

DES is associated with a measurable adverse impact on several common and important tasks of daily living, further implicating this condition as an important public health problem deserving increased attention and resources.