Elsevier

Nutrition Research

Volume 29, Issue 3, March 2009, Pages 164-172
Nutrition Research

Research Article
Education, but not occupation or household income, is positively related to favorable dietary intake patterns in pregnant Japanese women: the Osaka Maternal and Child Health Study

https://doi.org/10.1016/j.nutres.2009.02.002Get rights and content

Abstract

Although a large body of epidemiologic data accumulated in Western countries show that individuals with a higher socioeconomic position consume higher quality diets, information on such socioeconomic differences in the diets of non-Western populations, including Japanese, is absolutely lacking. This cross-sectional study examined the association of socioeconomic position with dietary intake in a group of pregnant Japanese women. Subjects were 1002 Japanese women during pregnancy. Socioeconomic position was assessed by education, occupation, and household income. Dietary intake was estimated using a validated, self-administered, comprehensive diet history questionnaire. Education was associated positively with intake of protein; total n-3 and marine-origin n-3 polyunsaturated fatty acids; dietary fiber; cholesterol; potassium; calcium; magnesium; iron; vitamins A, D, E, and C; and folate 9 and inversely with that of carbohydrate. No associations were seen between education and intake of total fat; saturated, monounsaturated, and total and n-6 polyunsaturated fatty acids; alcohol; or sodium. Regarding food, higher education was associated with a higher intake of vegetables, fish and shellfish, and potatoes and lower intake of rice. Education was not associated with intake of bread, noodles, confectioneries and sugars, fats and oils, pulses and nuts, meat, eggs, dairy products, or fruit. For occupation, housewives had a higher intake of dietary fiber, magnesium, iron, vitamin A, folate, and pulses and nuts than working women. Household income was not associated with any nutrient or food examined. In conclusion, education, but not occupation or household income, was positively associated with favorable dietary intake patterns in a group of pregnant Japanese women.

Introduction

In many Western countries, socioeconomic differences in health have been widely indicated, with higher socioeconomic position associated with better health [1], [2], [3]. Socioeconomic differentials in diet have also been observed. Dietary intake studies have consistently shown that individuals with a higher socioeconomic position consume higher-quality diets than those with a lower position, including higher intake of whole grains, lean meats, fish, low-fat dairy products, and fresh vegetables and fruits, and lower intake of fatty meats, refined grains, and added fats, resulting in higher intake of key vitamins and minerals and dietary fiber [4], [5], [6], [7], [8], [9], [10], [11], [12]. Given the important role of nutrition in promoting health, this dietary intake pattern may be linked to inequalities in health [12], [13].

Conversely, several Japanese studies have reported unclear or even inverse associations between socioeconomic position and health status. In a comparative analysis of Japan and England, Japanese men with a higher employment grade or education had a higher body mass index and waist-to-hip-ratio and lower (less favorable) high-density lipoprotein cholesterol level than those with a lower employment grade or education, whereas positive associations between socioeconomic position and health status were seen in England [14]. Other Japanese studies have observed unclear, rather than positive, associations of education and employment grade with several metabolic risk factors [15], [16].

To our knowledge, however, the presence of socioeconomic differences in Japanese diets has not been examined. Given the similarity of socioeconomic gradients in health and diet in Western countries vs the differences in socioeconomic gradients in health between Western countries and Japan, the associations between socioeconomic position and diet between Western countries and Japan may differ. In addition, the association between socioeconomic position and diet has been poorly investigated among pregnant women, even in Western countries [17], [18], [19], [20], [21].

Here, using baseline data from the Osaka Maternal and Child Health Study (OMCHS), we conducted a cross-sectional study of the association between socioeconomic position and dietary intake in a group of pregnant Japanese women. We hypothesized that the association between socioeconomic position and dietary intake in Japanese somewhat differs from that observed in Western populations.

Section snippets

Subjects

The subjects in this analysis were participants in the baseline survey of the OMCHS, an ongoing prospective cohort study investigating preventive and risk factors for maternal and child health problems. Details of the OMCHS have been published elsewhere [22], [23]. Briefly, all pregnant women in Neyagawa City, Osaka Prefecture, were recruited between November 2001 and March 2003. Of 3639 eligible women, 627 (17.2%) took part in the study. An additional 375 pregnant women living in other

Results

Socioeconomic and dietary characteristics of the 1002 pregnant women are shown in Table 1. The percentage of women in the low, medium, and high education groups was 32%, 41%, and 27%, respectively, with about 71% housewives and 29% outside workers. Median household income was 3 000 000 yen, ranging from 280 000 to 9 500 000 yen, with the percentage of women in the low, medium, and high categories of 31%, 38%, and 31%, respectively. Mean percentages of intake of protein, total fat, and

Discussion

In this cross-sectional study of a group of pregnant Japanese women, higher education was associated with favorable dietary intake patterns, such as a higher intake of protein, total and marine-origin n-3 polyunsaturated fatty acids; dietary fiber; potassium; calcium; magnesium; iron; vitamins A, D, E, and C; and folate and a higher intake of vegetables, fish and shellfish, and potatoes. Conversely, occupation and household income did not seem to be materially associated with dietary intake,

Acknowledgment

We thank the Neyagawa City Government, Hirakata City Government, Katano City Government, Shijonawate City Government, Kaizuka City Government, Takaishi City Government, Hannan City Government, Neyagawa City Medical Association, Hirakata City Medical Association, and Kadoma City Medical Association for their valuable support, and Tomoko Shibazaki, Nahoko Nishimura, and Naomi Takaoka for their assistance. This study was supported by a Grant-in-Aid (13770206, 16790351) for Scientific Research from

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    Other members of the Osaka Maternal and Child Health Study Group are listed in the Acknowledgments.

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