In recent decades, rapid economic growth in developing countries has brought about drastic changes in people's lifestyles. Such changes have been observed at both the individual level [e.g., changes in diet, physical activity and disease profiles (Monda et al., 2007)] and societal level [e.g., changes in infrastructure, land use, transportation planning and urban design (Popkin, 2001)]. The combined effects of this process of change have been termed “modernization.”
It has been suggested that modernization is a psychological stressor (Brown, 1982; Jenner et al., 1987; Pearson et al., 1993). For example, using the urinary concentration of catecholamine as a biomarker of psychological stress, Pearson et al. (1993) showed that Samoan adults who resided in Honolulu, the provincial capital of Hawaii, the United States of America, had higher levels of psychological stress than their counterparts living in rural Western Samoa. Similarly, McDade et al. (2000a) used another biomarker of psychological stress—Epstein-Barr virus (EBV) antibody titer—to highlight how urban children and adolescents had higher psychological stress than their rural peers in Western Samoa.
As yet, however, little attention has been paid to whether there might be inter-individual variation in psychological stress within modernizing rural populations. This may be an important gap in our knowledge especially as some evidence suggests that the modernization process has induced diversification in the lifestyle of individuals (e.g., types of activity and diet), even within rural areas (Adelman and Morris, 1973). Moreover, social comparison theory provides a mechanism for explaining how diversification within what were once homogenous communities might play a role in deteriorating psychological health. It highlights how the perception of an undesirable difference in lifestyle parameters with other community members, especially those whom a person believes to be comparable to him or herself (defined as a reference group), may be detrimental in terms of increasing the psychological stress of those who fare worse in the comparison (Festinger, 1954). Given this, investigating different types of lifestyle in such an environment might shed light on the impact that modernization has on local residents' psychological stress due to the changes it brings about in different forms of behavior (i.e., lifestyle).
This study was conducted among rural communities in Hainan Island, China. People in the rural communities in this location lived generally impoverished lives until the 1990s. However, from the late 1990s onwards rapid economic development occurred there and the communities as a whole became much wealthier. One result of this was that people's lifestyles increasingly diversified. The authors' observations among the local communities on the island suggest that there may have been two typical changes in lifestyle. First, there has been a change in some aspects of dietary behavior. In particular, after the year 2000 the population started to consume meat on a regular basis (Jiang et al., 2006). In traditional society, meat was rarely consumed as it was served exclusively on special occasions in Hainan Island. At that time, the regular consumption of pork was merely an aspiration and symbol of an ideal life for local residents. Second, commercial goods such as the motorbike, television, and mobile phone were introduced into the communities. For example, research by the authors has highlighted how by 2009, many of the households in one of island's rural communities owned televisions and tractors, and some owned mobile phones and motorbikes, whereas both poverty and a lack of electricity prevented residents from owning such durables before the late 1990s (Inoue et al., 2012).
Since the lifestyle changes induced by the process of modernization might not be uniform and might affect people's psychological status differently, even within a single community, the authors examined two major components of lifestyle change: diet and the possession of commercial goods. These were chosen to reflect different aspects of the change and its potential to impact on psychological stress, to better understand the psychological consequences of modernization in the rural areas of Hainan Island.
The objective of this study was to investigate the relation between changes in two conventional lifestyle markers, i.e., diet and the possession of commercial goods and psychological stress in the rural communities in Hainan Island, China, using EBV antibody titer as a biomarker of psychological stress.
- Top of page
- LITERATURE CITED
Descriptive statistics for age, BMI, prevalence of marriage and EBV antibody titer of the participants by region and sex are presented in Table 1. Results of the two-way ANOVA indicated that age did not differ by sex or region, but BMI was significantly different by region (P < 0.001). Participants in Wuzhishan region had a comparatively higher BMI than those in Baoting. The proportion of married participants was much higher among females than males (P < 0.001). Log-transformed EBV antibody titer ranged from 1.31 to 2.41 log EUs with a mean and standard deviation of 1.79 and 0.25 for male participants, and 1.91 and 0.25 for female participants, respectively. This meant that it differed significantly by sex (P < 0.001). It also differed significantly by region (P = 0.041). More specifically, females had higher EBV antibody titer scores than males, while participants in Baoting region had higher EBV antibody titer scores than participants in Wuzhishan region.
Table 1. Characteristics of the study participants by sex and region
| ||Wuzhishan||Baoting||Two-way ANOVA|
| ||n = 50||n = 58||n = 55||n = 58|| ||P-value|| |
|Age (year)a||39.4 ± 11.7||39.0 ± 11.8||40.2 ± 11.4||39.8 ± 11.4||0.797||0.618||0.998|
|BMI (kg/m2)a||21.6 ± 2.5||22.4 ± 2.5||20.7 ± 2.9||20.4 ± 3.0||0.536||<0.001||0.152|
|Marriage (%)||68.0||93.1||61.8||84.5||<0.001b||0.154b|| |
|log-EBV (EU)a||1.77 ± 0.24||1.86 ± 0.25||1.80 ± 0.26||1.96 ± 0.24||<0.001||0.041||0.264|
Information about the respondents' education level, their weekly consumption frequency of the eight selected food items, and monthly mobile phone fees by region and sex is presented in Table 2. More than 38% of the participants had an education level of less than 9 years (equivalent to graduation from middle school in China), while 6.4% had an education level of more than 9 years. Pork was the most commonly consumed food item; the median value of its consumption frequency was 2.5 times a week, while the other seven items were rarely consumed with the median values of at most once a week. These data support the authors' observation that pork consumption was the only food item that varied among local residents. The median value of the monthly mobile phone fee was 20 RMB.
Table 2. Socioeconomic status and lifestyle characteristics of the participants
|Less than 9 years||48.0||44.6||22.2||37.9||38.1|
|Equal to 9 years||48.0||51.8||63.0||58.6||55.5|
|More than 9 years||4.0||3.6||14.8||3.4||6.4|
|Consumption of foods (times/week)||Median (Inter-quartile range)|
|Pork||3 (1–4)||2 (1–3)||2 (1–3)||3 (2–3)||2.5 (1–4)|
|Beef||0 (0–0)||0 (0–0)||0 (0–0)||0 (0–0)||0 (0–0)|
|Chicken||1 (0.1–2)||0.5 (0–1)||1 (0–1)||1 (0–2)||1 (0–1)|
|Egg||0 (0–0)||0 (0–1)||0 (0–1)||0 (0–1)||0 (0–1)|
|Marine fish||1 (0.5–4.8)||1 (0–3)||1 (0.3–2)||2 (1–3)||1 (0.5–3)|
|River fish||1 (0–2)||1 (0–2)||1.5 (0–3)||1 (0–2)||1 (0–2.8)|
|Blood of animals||0 (0–0.1)||0 (0–0.2)||0 (0–0)||0 (0–0)||0 (0–0)|
|Noodles||0 (0–1)||0 (0–1)||0 (0–0)||0 (0–1)||0 (0–1)|
|Mobile phone fee (RMB/month)||20 (0–50)||20 (10–41.9)||30 (0–50)||0 (0–30)||20 (0–49)|
Table 3 shows the results from the least-squares regression analysis that was used to investigate the association between log-transformed EBV antibody titer (dependent variable) and age, sex, BMI, and region. A positive association was observed between age and EBV antibody titer (P = 0.041). An association was also seen between sex and EBV antibody titer (where it was higher in females, P < 0.001).
Table 3. Least-squares regression analysis between log-transformed EBV antibody titer and characteristics of the participants
| || ||n = 221|| |
|Sex (ref. female)||−0.128||0.033||<0.001|
|Region (ref. Baoting)||−0.064||0.035||0.066|
| || ||R2 = 0.095|| |
Table 4 shows the results of the least-squares regression analyses that investigated the associations between log-transformed EBV antibody titer (dependent variable) and the weekly frequency of pork consumption (Model 1), monthly mobile phone fees (Model 2), and the TAI and ITI (Model 3) after adjusting for the effects of age, sex, BMI, and region. A positive relation was observed between the frequency of pork consumption and EBV antibody titer (coefficient = 0.081, P = 0.040), while a negative association was found between monthly mobile phone fees and EBV antibody titer (coefficient = −0.078, P = 0.028). The results from the model investigating the association between EBV antibody titer and TAI and ITI revealed that ITI was negatively associated with EBV antibody titer (coefficient = −0.550, P = 0.002), while TAI had no statistically significant association.
Table 4. Least-squares regression analysis between log-transformed EBV antibody titer and lifestyle parameters and the total affluence index and investment tendency index
|Model 1a|| ||n = 220|| |
|Pork (ref. less than median)b||0.081||0.039||0.040|
|Sex (ref. female)||−0.136||0.034||<0.001|
|Region (ref. Baoting)||−0.071||0.035||0.042|
| || ||R2 = 0.113|| |
|Model 2a|| ||n = 221|| |
|Mobile (ref. less than median)b||−0.078||0.035||0.028|
|Sex (ref. female)||−0.117||0.033||0.001|
|Region (ref. Baoting)||−0.065||0.034||0.060|
| || ||R2 = 0.115|| |
|Model 3|| ||n = 220|| |
|Sex (ref. female)||−0.110||0.034||0.001|
|Region (ref. Baoting)||−0.064||0.034||0.062|
| || ||R2 = 0.135|| |