美视力损害10年增21% 糖尿病或为元凶

《美国医学会杂志》12月12日发表的一项研究显示，近十年的统计数据显示，美国普通成人的非屈光性视力损害现患率增加了21%，这可能与糖尿病患病率增加相关(JAMA 2012;308:2361-8)。

流行病学研究显示，1990年任何类型糖尿病的现患率为4.9%，1998年增至6.5%，2001年增至7.9%，2007年增至10.7%，2010年增至11.3%。约翰·霍普金斯大学达纳眼科预防中心的Fang Ko博士及其同事猜测，非屈光性视力损害现患率可能随糖尿病现患率的增加而增加。他们采用全美健康与营养调查(NHANES)的数据，比较了美国成人1999~2002年(第一研究期)与2005~2008年(第二研究期)的非屈光性视力损害现患率。NHANES每年抽取约10,000例具有全国代表性的成人样本进行健康相关问题的调查。NHANES参与者接受包括视力评估在内的广泛体格检查。共8,790例成人在第一研究期内完成视力检查，9,762例在第二研究期内完成视力检查。

结果显示，非屈光性视力损害现患率从第一研究期的1.4%增至第二研究期的1.7%，相对增加21%。多因素分析显示，与视力障碍相关的因素包括老龄、贫穷、教育程度低和糖尿病。在这两个研究期间出现增加的唯一危险因素是糖尿病。该研究人群的总体糖尿病现患率从第一研究期的6.5%增至第二研究期的8.2%，病程至少10年的糖尿病现患率从2.8%增至3.6%。

研究者表示，除了糖尿病之外，未发现其他可解释非屈光性视力损害现患率增加的原因。在无糖尿病的受试者中，非屈光性视力损害的现患率从第一研究期的1.2%增至第二研究期的1.4%。在糖尿病患者中则从3.7%增至5.3%。

此外，非屈光性视力损害的现患率随糖尿病病程增加而增加。研究者在一项额外分析中校正糖尿病状况后发现，两个研究期的非屈光性视力损害现患率无差异。

在所有人种和种族组中，在最年轻成人(20~39岁)中观察到的非屈光性视力损害现患率的绝对增幅最大，这与以下假说一致，即美国较年轻居民中日益增加的糖尿病现患率及增加的糖尿病病程可能与视力恶化相关。在年龄≥60岁的墨西哥裔美国人中观察到的增幅也特别大(从4.6%增至8.9%)。

研究者表示，如果上述研究结果被证实并且这种趋势持续存在，可导致美国人的致残率增加，需要接受眼科治疗的终末器官糖尿病性损害患者的数量也将增加。

该研究获美国疾病预防控制中心和支大卫·弗里德曼研究补助金奖支持。Ko博士声明从Pepose获得资金，一位研究者声明与数家眼科产品生产商存在联系。

随刊述评：短期内非屈光性视力损害现患率增加显著

密歇根大学安娜堡分校眼科的David C. Musch博士和Thomas W. Gardner博士表示，虽然非屈光性视力损害现患率绝对增幅较小(0.3%，从1.4%增至1.7%)，但将这一百分比外推至所有美国成人的话，其效应较为显著。美国≥20岁的人口约为2亿3千万，0.3%的增幅意味着在相对较短的时间内增加约700,000例非屈光性视力损害患者(JAMA 2012;308:2403-4)。

基于该研究结果，儿科医生、家庭医生、内科医生和眼科医生应留意2型糖尿病患者的视力状况。

Musch博士和Gardner博士均声明无相关经济利益冲突。

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By: MARY ANN MOON, Clinical Endocrinology News Digital Network

The prevalence of nonrefractive visual impairment rose 21% in the general U.S. adult population during the most recent decade for which statistics are available, and that increase may be related to the recent rise in the rate of diabetes, according to a reportin the Dec. 12 issue of JAMA.

In what they described as the first study to have noted this increase in the visual disorder, researchers found that the overall prevalence of nonrefractive impairment among adults in the United States rose from 1.4% in 1999-2002 to 1.7% in 2005-2008.
     
Notably, the largest absolute increase occurred in the youngest adults, those aged 20-39 years, across all racial and ethnic groups. The elevation also was particularly large among Mexican Americans aged 60 and older, among whom it rose from 4.6% to 8.9%, said Dr. Fang Ko of the Dana Center for Preventive Ophthalmology, Johns Hopkins University, Baltimore, and her associates.

Nonrefractive visual impairment refers to a presumably organic eye disorder that impairs vision and cannot be corrected with eyeglasses. The most common causes are age-related macular degeneration, cataracts, diabetic retinopathy, and glaucoma.

Dr. Ko and her colleagues hypothesized that the prevalence of nonrefractive visual impairment may be increasing along with the increasing prevalence of diagnosed diabetes that has been reported in the literature. Rates of any type of diabetes rose from 4.9% in 1990 to 6.5% in 1998, 7.9% in 2001, 10.7% in 2007, and 11.3% in 2010, according to epidemiologic studies.

The investigators analyzed data from the National Health and Nutrition Examination Surveys (NHANES) to compare the prevalence of nonrefractive visual impairment in U.S. adults during 1999-2002 with that during 2005-2008. Conducted by the National Center for Health Statistics, NHANES examines health-related issues in nationally representative samples of approximately 10,000 adults every 2 years.

Participants in NHANES undergo extensive physical examinations that include vision assessments. A total of 8,790 adults completed a visual acuity exam during the first study period and 9,762 did so during the second study period.

The prevalence of nonrefractive visual impairment rose from 1.4% in 1999-2002 to 1.7% in 2005-2008, a relative increase of 21%.

In a multivariate analysis, factors that were associated with the visual disorder were older age, poverty, lower educational status, and diabetes. The only one of these risk factors that increased during the study periods was diabetes. In this study population, the overall prevalence of diabetes increased from 6.5% in 1999-2002 to 8.2% in 2005-2008, and the prevalence of diabetes of at least 10 years’ duration rose from 2.8% to 3.6%.

"Other than diabetes, we were unable to identify any other reason for increasing prevalence of nonrefractive visual impairment," Dr. Ko and her associates wrote (JAMA 2012;308:2361-8).

In study subjects who didn’t have diabetes, the prevalence of nonrefractive visual impairment was 1.2% in 1999-2002 and 1.4% in 2005-2008. In contrast, the prevalence of this type of visual impairment among subjects with diabetes was 3.7% in the first study period and 5.3% in the second.

In addition, the prevalence of nonrefractive visual impairment increased with increasing duration of diabetes.

And in an additional analysis of the data, controlling for diabetes status eliminated the difference in the prevalence of nonrefractive visual impairment between the two study periods.

The largest absolute increase in the prevalence of the eye disorder occurred in the youngest adults, which "is consistent with the hypothesis that increasing prevalence of diabetes among younger U.S. residents, with subsequent increasing duration of diabetes, may be related to worsening vision," the investigators said.

If the study findings are confirmed and this trend persists, "it could result in increasing rates of disability in the U.S. population, including greater numbers of patients with end-organ diabetic damage who would require ophthalmic care," they added.

This study was supported by the Centers for Disease Control and Prevention and the David Friedman Research Grant Award. Dr. Ko reported receiving a grant from Pepose, and one of his associates reported ties to several makers of ophthalmologic products.

My Take

A substantial increase over a short time

A 0.3% absolute increase – from 1.4% to 1.7% – in the prevalence of this type of visual impairment may seem small, but extrapolating these percentages to the entire U.S. adult population shows that the effect is substantial, said David C. Musch, Ph.D., and Dr. Thomas W. Gardner.

"With about 230 million people aged 20 years or older in the U.S. population, a 0.3% increase could potentially represent an increase of almost 700,000 individuals with nonrefractive visual impairment over a relatively short time," they noted.

"This report should send an important message to pediatricians, family practitioners, internists, and ophthalmologists who already are seeing an increase of type 2 diabetes among their younger patients."

DR. MUSCH is in the departments of ophthalmology and visual sciences and of epidemiology at the University of Michigan, Ann Arbor. DR. GARDNER is in the departments of ophthalmology and of molecular and integrative physiology at the university. They reported no relevant financial conflicts of interest. These remarks were taken from their editorial accompanying Dr. Ko’s report (JAMA 2012;308:2403-4).