Loneliness as a Risk Factor for Hypertension in Later Life

Abstract

Objective: The present study aims to determine the impact of loneliness on hypertension in later life. Method: Data for this study are derived from a sample of 1,880 older Malaysians via a cross-sectional survey entitled “Patterns of Social Relationships and Psychological Well-Being Among Older Persons in Peninsular Malaysia.” Loneliness is assessed by the PGCMS item, “How much do you feel lonely?” Data analysis is carried out using the Statistical Package for Social Sciences (SPSS) version 19.0. Results: Nearly one third of respondents report high level of loneliness. The overall prevalence of hypertension is 39% (95% CI = 36.9-41.3). Logistic regression, controlling for sociodemographic factors and several chronic medical conditions, shows that loneliness significantly increases likelihood of hypertension in later life (OR = 1.31, p ≤ .05, 95% CI = 1.04-1.66). Discussion: The results show loneliness as a major risk factor for hypertension and call for health care professionals to be aware of the negative physiological effects of loneliness in old age.

Keywords

aged hypertension loneliness Malaysia

Introduction

Hypertension, an increasingly important medical and public health issue, has long been recognized as one of the most important risk factors for stroke and death in older adult population (Moore, 2005; Mosley Ii & Lloyd-Jones, 2009; Rabkin, Mathewson, & Tate, 1978). Although all age groups are at risk of hypertension, studies have highlighted the increase in hypertension rates among aging population (Chobanian et al., 2003; Johnston, Propper, & Shields, 2009; Rampal, Rampal, Azhar, & Rahman, 2008), where more than 50% of people aged between 60 and 69 years and about 75% of those aged 70 years or older are affected (Chobanian et al., 2003). Similarly, it is widely acknowledged that hypertension is a major public health problem in Malaysia, especially among older adults (Mohd Sidik, Mohd Zulkefli, & Mustaqim, 2003; Rampal et al., 2008; Srinivas, Wong, Chia, Poi, & Ebrahim, 1998; Teo & Idris, 1996).

Although several studies have documented the role of heredity, lifestyle (Buck, Williams, Musick, & Sternthal, 2009), and socioeconomic status (SES; Gorman & Sivaganesan, 2007; Lim & Morad, 2004; Rampal et al., 2008) in the occurrence of hypertension, the relationship between aging and hypertension has a solid pathophysiological basis (McNeil & Silagy, 1991; Timby & Smith, 2004). Since the incidence of hypertension increases with age it is imperative to understand the factors contributing to hypertension in late life (Moore, 2005; Mosley Ii & Lloyd-Jones, 2009). In light of this consideration, the potential role of psychosocial factors, particularly loneliness in old age, is less well understood. The idea that loneliness may contribute to hypertension is slightly new and needs to be studied further.

Loneliness is defined as an individual’s subjective perception, both quantitatively or qualitatively, which results from lack of satisfying human relationships (Patterson & Veenstra, 2010; Tilvis, Laitala, Routasalo, & Pitkala, 2011). Similarly, it has been defined as a psychological experience with potentially adverse effects on biological stress processes (Steptoe, Owen, Kunz-Ebrecht, & Brydon, 2004).

Loneliness is well documented as a prevalent problem among older adults, due to life changes and losses in old age (Park & Chang, 2004), with a prevalence rate up to 40% (Holmén, Ericsson, Andersson, & Winblad, 1992; Savikko, 2008).

However, scientific investigations show that loneliness is negatively associated with physical and mental health (Park & Chang, 2004; Penninx et al., 1999); it has been neglected in the medical training and literature (Luanaigh & Lawlor, 2008; Paul & Ribeiro, 2009; van Ravesteijn, Lucassen, & van der Akker, 2008). Considering the association of loneliness with adverse health outcomes, increased attention should be paid to this topic.

This study aims to find the prevalence of loneliness among the community-dwelling older Malaysians as well as to determine the impact of loneliness on occurrence of hypertension among the said category of individuals. The results might persuade many doctors to pay increased attention to this topic. Findings may also encourage professionals working with older adults to design an effective program to reduce loneliness that may contribute toward lowering hypertension and preventing premature death in old age.

Method

The data presented in this paper were drawn from the Malaysian National Survey entitled “Patterns of Social Relationships and Psychological Well-Being Among Older Persons in Peninsular Malaysia” (PSRPWO), whose detailed methodology has been published elsewhere (Loke, Abdullah, Chai, Hamid, & Yahaya, 2011). In brief, the PSRPWO was a cross-sectional, face-to-face, interviewer-administered survey of 1,880 community residents aged 60 years or older from Peninsular Malaysia. A multistage cluster sampling technique was used to obtain a representative sample of Malaysian population. The characteristics of the sample broadly represented the general population of older people living in the community in Peninsular Malaysia. The survey collected several and diverse information, but for this article “loneliness and hypertension” were of special interest.

Measures

Loneliness

Loneliness was measured by the Philadelphia Geriatric Center Morale Scale (PGCMS) item, “How much do you feel lonely?,” with not much scored as 1 and a lot scored as 2 (Lawton, 1975); this item has previously been used in several studies to measure loneliness (Levy & Myers, 2005; Levy, Slade, Kunkel, & Kasl, 2002).

Hypertension and other chronic conditions

Hypertension and other chronic medical conditions were assessed by self-report questions concerning presence/absence of each condition. Interviewers asked respondents, “Have you ever been told by a doctor that you have the following chronic medical conditions?” This method is widely used in population studies and provides an accurate estimate of prevalence of chronic medical conditions (Goldman & Lin, 2003; Martin, Leff, Calonge, Garrett, & Nelson, 2000; Momtaz, Hamid, Yahaya, & Ibrahim, 2010).

Control Variables

In order to control for the potential confounding influence of age, sex, marital status, ethnicity, and educational attainment, these variables were used as covariates in logistic regression. We also adjusted for presence of diabetes, heart disease, kidney disease, and hypercholesterolemia.

Data Analysis

The preliminary analysis used chi-square tests to examine the associations between hypertension and specific risk factors. Logistic regression was used to calculate the adjusted odds ratio for the association between hypertension and loneliness, after controlling for possible sociodemographic factors such as age, sex, marital status, ethnicity, and chronic medical conditions, including hypercholesterolemia, kidney disease, heart disease, and diabetes. Statistical Package for the Social Sciences (SPSS, version 19) was used to carry out descriptive and inferential statistical analyses.

Results

The sample for this study consisted of 1,880 community-dwelling older Malaysians comprising 52.6% women and 47.4% men. Table 1 presents the sociodemographic characteristics and health status of the sample. The mean age of the respondents was 69.8 years (SD = 7.36). Slightly more than 56% were married. In terms of loneliness, approximately one third (29.3%) of the respondents reported that they experience “a lot” of loneliness.

Table 1.

Sociodemographic Characteristics and Health Status of the Sample

Variable	Category	N	%
Age	60-69	1,025	54.5
	70-79	636	33.8
	80+	219	11.6
Sex	Female	989	52.6
	Male	891	47.4
Marital status	Unmarried	823	43.8
	Married	1,057	56.2
Education	No formal education	713	37.9
	Primary	972	51.7
	Secondary/tertiary	195	10.4
Loneliness	Not much	1,329	70.7
	A lot	551	29.3
Household income	Below poverty line	529	28.1
	Above poverty line	1,351	71.9
Ethnicity	Non-Malay	459	24.4
	Malay	1,421	75.6
Kidney disease	No	1,848	98.3
	Yes	31	1.6
Hypercholesterolemia	No	1,751	93.1
	Yes	128	6.8
Heart disease	No	1,682	89.5
	Yes	197	10.5
Diabetes	No	1,494	79.5
	Yes	368	19.6

The overall prevalence of hypertension among older Malaysians was found to be 39% (95% CI = 36.9-41.3; Table 2). This rate was found to be as high as 44% (95% CI = 39.9-47.6) for those in the age range between 70 and 79 years and close to 32% (95% CI = 25.8-38.1) for those who were 80 years of age or older. Further findings showed that 35.4% (95% CI = 32.2-38.5) of men and 42.4% of women (95% CI = 39.3-45.4) reported having hypertension. The prevalence of hypertension among the 551 respondents who reported a lot of loneliness was 45.4 (95% CI = 41.2-49.5).

Table 2.

Distribution of Population According to Hypertension Status

		Hypertension (n = 734)		No hypertension (n = 1,146)
Variable	Category	n	%	n	%	p Value
Age	60-69	386	37.7	639	62.3	≤.01
	70-79	278	43.7	358	56.3
	80+	70	32	149	68
Sex	Female	419	42.4	570	57.6	≤.01
	Male	315	35.4	576	64.6
Marital status	Unmarried	354	43	469	57	≤.01
	Married	380	36	677	64
Education	No formal education	284	39.8	429	60.2	ns
	Primary	385	39.6	587	60.4
	Secondary/tertiary	65	33.3	130	66.7
Loneliness	Not much	484	36.4	845	63.6	≤.001
	A lot	250	45.4	301	54.6
Household income	Below poverty line	197	37.2	332	62.8	ns
	Above poverty line	537	39.7	814	60.3
Ethnicity	Non-Malay	151	32.9	308	67.1	≤.001
	Malay	583	41	838	59
Kidney disease	No	716	38.7	1,132	61.3	≤.05
	Yes	18	58.1	13	41.9
Hypercholesterolemia	No	640	36.6	1,111	63.4	≤.001
	Yes	94	73.4	34	26.6
Heart disease	No	608	36.1	1,074	63.9	≤.001
	Yes	126	64	71	36
Diabetes	No	460	30.8	1,034	69.2	≤.001
	Yes	262	71.2	106	28.8

Note: n = 1,880.

To evaluate association between hypertension, loneliness, sociodemographic factors, and chronic medical conditions, a series of chi-square tests were conducted that confirmed hypertension is not uniformly distributed across the older population. As shown in Table 2, the results of chi-square tests identified that hypertension is significantly associated with loneliness (χ² = 13.12, p ≤ .001); sociodemographic factors, including age (χ² = 11.26, p ≤ .01), sex (χ²= 9.68, p ≤ .01), marital status (χ²= 9.70, p ≤ .01), ethnicity (χ² = 9.64, p ≤ .01); and chronic medical conditions, including hypercholesterolemia (χ² = 68.18, p ≤ .001), kidney disease (χ² = 4.78, p ≤ .05), heart disease (χ² = 57.30, p ≤ .001), and diabetes (χ² = 203.06, p ≤ .001).

Logistic Regression

To control for possible confounding variables, a multivariate logistic regression model was conducted to examine effect of loneliness on hypertension. Table 3 illustrates the results from logistic regression analyses of potential risk factors for hypertension. Adjusting for sociodemographic factors and chronic medical conditions, results of logistic regression revealed older persons who reported a lot of loneliness (OR = 1.31, 95% CI = 1.04-1.66) had a significantly higher prevalence of hypertension as compared with older person with low level of loneliness, after controlling for possible sociodemographic and health factors. In other words, after controlling for possible confounding variables, the odds of hypertension for older persons with a lot of loneliness were 1.31 times greater than older persons with low loneliness. The other sociodemographic factors associated with hypertension included age (OR = 1.29, p ≤ .05, 95% CI = 1.02-1.63), sex (OR = 1.30, p ≤ .05, 95% CI = 1.01-1.65), ethnicity (OR = 2.01, p ≤ .01, 95% CI = 1.54-2.62), and education (OR = 1.45, p ≤ .05, 95% CI = 1.00-2.12). In addition, those with heart disease (OR = 2.15, p ≤ .001, 95% CI = 1.52-3.04), hypercholesterolemia (OR = 5.50, p ≤ .001, 95% CI = 3.47-8.72), and diabetes (OR = 5.09, p ≤ .001, 95% CI = 3.90-6.64) were more likely to report hypertension.

Table 3.

Adjusted Odds Ratio (AOR) of Hypertension Among Older Malaysians

Variable	B	SE	AOR	(95% CI AOR)
Loneliness	0.27	0.12	1.31*	1.04	1.66
Age (reference category: 60-69)
70-79	0.26	0.12	1.29*	1.02	1.63
80+	−0.27	0.18	0.76	0.53	1.09
Sex (reference category: male)	0.26	0.12	1.30*	1.01	1.65
Marital status (reference category: married)	0.08	0.12	1.08	0.85	1.38
Ethnicity (Malay)	0.70	0.14	2.01**	1.54	2.62
Education (reference category: secondary)
No formal	0.31	0.21	1.37	0.91	2.07
Primary	0.37	0.19	1.45*	1.00	2.12
Household income (reference category: below 529 Malaysian Ringgit (RM)	0.22	0.12	1.24	0.98	1.58
Hypercholesterolemia	1.71	0.24	5.50**	3.47	8.72
Heart disease	0.76	0.18	2.15**	1.52	3.04
Diabetes	1.63	0.14	5.09**	3.90	6.64
Kidney disease	0.19	0.44	1.21	0.51	2.87

Note: Hosmer and Lemeshow Test: χ²(8) = 14.00, p > .05, Nagelkerke R² = .22.

p ≤ .05. **p ≤ .001.

IUSD was equivalent to RM 3.75 at time of the data collection.

Discussion

This study is one of the few studies that investigated the impact of loneliness on hypertension in later life. The overall prevalence of self-reported hypertension in the current study (39%) was consistent with previous national (Rampal et al., 2008) and international (Heath, Browning, & Reed, 1999) rates. However, it was found to be much lower than the finding from a study among a group of older adults in Taiwan, where prevalence rates of hypertension were 53.09% in men and 56.06% in women (Lai et al., 2001). In addition, the prevalence rates of hypertension among older Americans and Canadians aged 65 years or older were 53.8% and 48.0%, respectively (Kaplan, Huguet, Feeny, & McFarland, 2010). In general, the findings from this study in line with previous scientific investigations illustrate a high prevalence rate of hypertension in old age.

Almost one third of our participants admitted to a lot of loneliness, which is consistent with the results of several other prevalence studies of loneliness in later life, where the rate of loneliness was found to be as high as 40% (Routasalo & Pitkala, 2003). In a Finnish survey, 39% of the 4,000 older persons surveyed reported feelings of loneliness (Routasalo, Savikko, Tilvis, Strandberg, & Pitkala, 2006). In addition, the prevalence of loneliness among older people in China was estimated at 29.6% in 2000 (Yang & Victor, 2008).

Overall, the result of our study supported previous studies documenting loneliness as a common and serious issue among older adults (Alma et al., 2011; Hawkley, Masi, Berry, & Cacioppo, 2006; Hawkley, Thisted, Masi, & Cacioppo, 2010; Routasalo & Pitkala, 2003; Theeke, 2009; William Lauder, Sharkey, & Mummery, 2004; Yang & Victor, 2008).The main purpose of this study was to examine the relationship between loneliness and the diagnosis of hypertension. The result of logistic regression, after controlling for confounding variables, supported that loneliness significantly increases the likelihood of hypertension in later life. This result was again consistent with the findings from both cross-sectional and longitudinal studies that showed that loneliness is associated with hypertension and coronary heart disease (CHD; Hawkley & Cacioppo, 2007; Hawkley et al., 2006, 2010; Sorkin, Rook, & Lu, 2002; Wang et al., 2011). The findings from the study conducted by Sorkin and colleagues found a significant association between loneliness and heart condition status, after controlling for other chronic health problems.

Although the mechanism by which loneliness causes hypertension is unclear (O’Luanaigh et al., 2012), it is possibly mediated through psychobiological pathways involving central nervous system activation of neuroendocrine, autonomic, and immune responses (Wang et al., 2011). In addition, there is some evidence that loneliness is associated with blunted autonomic response to stress, increased total peripheral resistance (TPR; Cacioppo et al., 2002), and raised levels of HbA1c (O’Luanaigh et al., 2012), and, consequently, hypertension.

The neuroendocrine pathways triggers several mechanisms, including activation of the hypothalamic-pituitary-adrenal system (HPA; Hawkley, Bosch, Engeland, Marucha, & Cacioppo, 2007), which are a result of elevated stress response linked with loneliness. The activation of HPA leads to an elevation in the stress hormone (cortisol) levels, which in turn leads to hypertension (Adams, Hawkley, Kudielka, & Cacioppo, 2006). Cortisol is also associated with several clotting factors, such as fibrinogen and von Willebrand factor (von Kanel, Mills, Fainman, & Dimsdale, 2001); consequently, these clotting factors increase the risk of hypertension.

Furthermore, lonely individuals are more vulnerable to stressors encountered in daily life (Hawkley & Cacioppo, 2003) and exhibit symptoms such as chronic changes in the autonomic nervous system, including an elevated sympathetic-adrenergic activation that leads to an elevation in stress responses, and hence, a higher risk of cardiovascular disease (Sorkin et al., 2002). This occurs via an increased vascular resistance coupled with age-related decrease in vascular compliance of the blood vessels and, consequently, leads to an increase in blood pressure (Cacioppo, 2009).

Other possible explanations include the likelihood that lonely individuals may be less inclined to utilize medical services or to use blood pressure medication (Hawkley et al., 2006). The lowering of services by medical care professionals to lonely clients also increases elevation in blood pressure as shown in a case–control study conducted by Cacioppo et al. (Cacioppo, Hawkley, & Berntson, 2003), wherein physicians, nurses, and ancillary staff provided better or more complete medical care to obviously nonlonely patients than to patients who appeared to be socially isolated. Although we did not include weight and body mass index of our participants, it has been shown that increased body mass index (BMI) is associated with hypertension. The result of a large cross-sectional survey (n = 1,289 adults; mean age = 46.3 years) revealed that lonely individuals had a higher mean BMI and a greater proportion of overweight/obese individuals than the nonlonely group (Lauder, Mummery, Jones, & Caperchione, 2006).

The last possible cause that may shed light on the effect of loneliness on blood pressure is depression. There is a growing body of literature that shows that loneliness significantly accentuates depression (Nolen-Hoeksema & Ahrens, 2002; Park & Chang, 2004). Consequently, several scientific investigations have found that depression is statistically linked to increased odds of hypertension and myocardial infarction (Jonas, Franks, & Ingram, 1997; Yary et al., 2010).

In summary, current findings, in line with existing knowledge, supported the idea that loneliness is one of the most important possible factors for increases in blood pressure levels in older adults.

Limitation and Implications

There are several strengths and limitations to this study that should be addressed. The strength of the study is mainly in the large representative sample of the older Malaysians population. The major limitation of this study includes the cross-sectional design, which rules out concluding that there is a causal relationship between loneliness and hypertension. The second limitation is the use of self-reported chronic medical conditions. A further limitation of this study involves the method used to measure loneliness, a single-item subjective self-report of loneliness; however, previous studies have found that this method is also an adequate measure of loneliness (Chlipala, 2008).

Although the associations between loneliness and common psychiatric problems in older adults have been previously studied (Golden et al., 2009; Vink et al., 2009; Vink, Aartsen, & Schoevers, 2008), the present study is constrained by the use of secondary data that did not measure depression and anxiety. In this case, it was not possible to determine either the associations of loneliness with anxiety and depression or the unique contribution of loneliness toward the two psychiatric conditions. Therefore, this limitation presents a unique avenue for the researchers to consider these variables in a follow-up study and for future research to determine whether loneliness can be a proxy marker for depression and anxiety or a better indicator for hypertension than either depression or anxiety.

Despite these limitations, to our knowledge, the present study is one of the few that addressed the relationship between loneliness and hypertension in later life. One of the most important practical implications of this study is that all mental health and other health professionals involved in geriatric care must be aware of the negative physiological effect of loneliness on hypertension and so should pay increased attention on this topic. In future, further prospective case–control study need to be done before a causal relationship can be established. Loneliness is a modifiable risk factor that can be improved through a social intervention program that may contribute to lowering the incidence of hypertension in old age. In addition, it should be treated as a “geriatric giant,” due to its potential in causing mortality and morbidity; therefore, detection of loneliness is crucial in management and treatment of older patients.

Footnotes

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The researchers would like to acknowledge the Ministry of Science, Technology and Innovation for the financial support under Grant No: 04-01-04-SF0479.

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